What is a T1 Router?

You may already have a broadband router or an IP network router, but what is a T1 Router?

A T1 router is simply a router with the necessary interface circuitry to connect directly to a T1 line. Often, it is set up as an Internet access router to provide dedicated Internet service to an organization's computer networks. Other T1 routers are used to connect local area networks to each other through T1 private lines.

Why the special interfacing? A T1 line can carry your network traffic, but it is not inherently an IP or Ethernet format service. T1 service was originally designed to carry multiple telephone lines that had been digitized. It still serves that purpose to provide a cost advantage in connecting a dozen or more telephone lines to a PBX system. As such, T1 uses a proprietary protocol based on synchronous time division multiplexing rather than the packet switching protocol that is the current standard for nearly all local area networks.

You don't have to worry about the messy business of timing, framing and line coding. A T1 router takes care of the necessary conversions transparently. The T1 line from the "smart jack" provided by the telephone company installers plugs into one port of the T1 router. Your network plugs into another. Once it is setup to meet the requirements of both the T1 line and your LAN, you have a gateway for network traffic to the Internet or another business location.

So normal routers don't work with T1 lines? Yes and no. You can connect a regular IP based router to a T1 line using a couple of specialized interface boxes called CSUs and DSUs. The CSU or Channel Service Unit is the device that connects directly to the T1 line at the telco demarcation point. It handles the electrical interface between the bipolar T1 signals and the digital signals used by networking equipment. It also provides a "loopback" function so that correct operation of the T1 line can be checked remotely by the T1 line carrier. The DSU or Data Service Unit works something like a modem to convert the packet network signals to and from the TDM format used on the T1 line. Usually the CSU and DSU are combined into one piece of equipment called a CSU/DSU.

What makes a T1 router is the CSU/DSU circuitry that is built into the router chassis or available as a plug-in module. With router and CSU/DSU in one box, you have the convenience of a single device to handle the WAN or wide area network connection to a T1 line. You can also get T3 routers if you need more bandwidth. A T3 router can handle the higher speed network traffic of a 45 Mbps T3 line and has the CSU/DSU interface particular to T3 circuits.

You could go out and buy your own T1 router or perhaps a plug in module for your current network router. But it may make more sense to let your T1 carrier provide the T1 router as well as the line service. Many T1 providers will give you the router at no charge or a small increase in the monthly T1 lease charge. You save the cost of hundreds or even thousands of dollars of capital investment in router hardware. Plus the T1 carrier can now manage the T1 line through the router interface and right up to your network connection. That makes troubleshooting much easier than if you have multiple pieces of equipment from multiple vendors.

Don't buy a T1 router until you see if you can get one free with your T1 line service through T1 Rex.

VoIP Telephone Service With New Discount

Packet8, an important player in the business and residential VoIP telephone service market, has recently made some strategic marketing moves. We've just been given permission to offer you Packet8 Virtual Office, video phone and consumer VoIP services with a special $19.95 activation discount. I'll tell you how to get it in minute. Saving $19.95 is like getting a month's free service on the residential VoIP and video phone services, and a nice discount on the Virtual Office business service. Here's a quick update on these VoIP services and their current pricing.

Packet8 broadband phone is priced at $19.95 a month for unlimited U.S. and Canada calls. You get a broadband phone adaptor, also called an ATA (Analog Telephone Adaptor), that connects the regular telephone you have now to your DSL or Cable broadband service.

Note that Packet8 broadband phone service is intended for residential users in the USA. If you live outside of the U.S., the Packet8 Freedom International plan allows you to have a U.S. phone number and make up 1,000 minutes of calls to United States and Canadian phone numbers for just $19.95 (US) per month plus activation. Also note that while Packet8 offers E911 emergency service in many areas, you need to sign up separately for this and pay an extra monthly fee.

Packet8 Video Phone service is now also priced at $19.95 a month plus activation, and the video phone is only $99. These are the same video phones that used to be $250 each. Both parties on the call need to have a Packet8 video phone and service account. This is a stand-alone video phone with a high quality color picture and full motion. It makes some of the older expensive corporate video conferencing systems look lame by comparison.

Virtual Office is an enterprise VoIP service that gives you a hosted PBX service with such niceties as auto-attendant and conference bridge. Each extension phone is $99 plus activation and $39.95 a month for unlimited local and long distance US business calls. A big advantage of hosted PBX is that your VoIP phones can be located anywhere, not necessarily in the same building or even the same state.

Internet Web Conferencing Gets Cheap and Easy

Email, FAX and even snail mail works fine when all you need to do is get a document from place to place. But business slows to a snail's pace if you try to use these methods for collaboration on a project. Try sending your slide presentation out for evaluation through the mail and you'll feel like you've been beamed back to the 18th century, when you had to wait 3 months for the next ship to get your documents from the old country.

Here's where Internet web conferencing gets the review and comment process up to warp speed. Imagine popping up a window on your PC and seeing a proposed slide presentation hosted by someone on the other side of the world. Then imagine being given control of that presentation so that you can add your own input. Your 10 member team is all online at the same time, chatting back and forth while you take turns presenting material or making your comments in real time. That's what you can do with web conferencing services.

Internet web conferencing is a step beyond online alternatives such as sending emails back and forth, posting content on a web site or forum, or even real-time chat. It adds a graphical presentation function so you can display your creative work while hosting real-time chat for feedback. You can also add telephone conferencing so you can talk to everyone on the phone while you share written and graphical material online.

Web conferencing services have been around for awhile, but they've tended to be too expensive for casual use or smaller groups. You might have to buy individual seats for each participant and pay hundreds of dollars a month to hold your conferences. A cheap web conferencing solution from Citrix called GoToMeeting offers a way for you to get into web based conferencing at a more reasonable price. There's even a free trial available so you don't have to actually buy the service until you know it will meet your needs.

With GoToMeeting, you pay a low fixed monthly or annual fee and host all the meetings you want for no additional charge. The only limitation is that there is a maximum of 10 participants on each meeting. If you have larger groups, you get GoToMeeting Corporate for up to 25 seats and you can even get a special event license for up to 200 participants.

How does it work? The meeting organizer sends out invitations to the intended participants by email or instant messaging. Each participant needs to download a small applications program to their computer. At the time of the meeting, you simply click on the link in your invitation and you become part of the meeting. If there is a simultaneous telephone conference, you dial into that system also.

One of the more exotic features of GoToMeeting is that the meeting leader can transfer control of their mouse and keyboard to another participant. You get to share any application or file on your desktop, which is great for getting input on new products or collaborating on group documents. Your information is protected by passwords, unique meeting IDs, SSL and 128-bit AES encryption to keep eavesdroppers and other evil-doers out of your presentations.

In addition to being able to have a non-colocated team collaborate on a group project, Internet web conferencing is also a way to make presentations to customers and potential clients without the need to physically travel. You not only save the travel expense, but you can get your presentation in front of the client instantly instead of a day or two later.

If you would like to try cheaper, easier Internet web conferencing to see if will work for your team or organization, you can get the GoToMeeting free trial offer right now.

What's The Bandwidth of a T1 Line?

T1 lines are high speed digital telecommunications circuits. They are typically used to carry digitized phone calls, including the traditional TDM (time division multiplexing) format used by legacy PBX systems and telecom carriers as well as the newer VoIP broadband phone. Other applications of T1 lines are dedicated broadband Internet service, ISP backbones to the Internet, audio and video transport, and point to point private lines between business locations. These applications all require what is called broadband or high bandwidth digital transmission speeds.

The basic bandwidth of a T1 line is 1.544 Mbps in both directions. It is a bidirectional or symmetrical service. It is also full duplex, allowing transmissions to take place simultaneously on the upstream and downstream paths without interference. This is especially important when T1 lines are used to carry telephone calls. Both parties need to be able to both talk and listen at the same time. Otherwise, phones would work more like walkie-talkies or CB radios where only one party can talk at a time.

The usable bandwidth of a T1 line is a little bit less than the line speed of 1.544 Mbps. That's because 8 Kbps of that speed is used for framing, which is a technique for keeping the line synchronized by constantly transmitting a unique framing pattern using a special framing bit. The equipment at the receiving end of each path in the T1 circuit looks for the framing pattern and uses it to know exactly where each frame starts. Deduct that 8 Kbps for framing and you have 1.536 Mbps of usable bandwidth, also called the payload. The payload is the bits that you get to put on the line.

The synchronous nature of a T1 line means that you can divide it into 24 unique channels. Each frame will have 1 framing bit and 24 channels of 8 payload bits each. Why this division? It's the original specification for digitized phone calls. Each channel carries one call of 8 bits sampled 8,000 times per second. That's 64,000 bits per second or 64 Kbps per channel. Take 24 channels at 64 Kbps per channel and you have 1,536 Kbps or 1.536 Mbps as the payload capacity of your T1 line.

Of course, you don't need to break the T1 line into channels if you don't need that feature to support multiple telephone lines for a PBX system or a bank of dial-up modems. You can have the T1 line set up as unchannelized, which gives you frames of 192 bits each. You get the same 8,000 frames per second. The 192 payload bits per frame times 8,000 frames per second is also 1.536 Mbps.

Need more bandwidth than this? Try bonding 2 T1 lines together for double the payload or 3.072 Mbps. You can continue to bond T1 lines up to 6 lines, which gives you 9.216 Mbps. Beyond that, you can move up to T3 or DS3 service which runs at 44.736 Mbps and gives you the equivalent of 28 T1 lines or 672 voice channels of 64 Kbps each. That's a usable bandwidth of 43.008 Mbps.

If your business has need for high bandwidth digital service, let T1 Rex help you find the lowest T1 line prices and T3 line prices with service level agreements.

Receive and Send Faxes Online

Internet fax services are replacing the traditional fax machine for both sending and receiving fax messages. No fax machine? So what takes the place of the photodiode scanner and thermal or ink cartridge printer? Is this the same as fax software?

No, not fax software. This is an Internet based application that uses your email client or web browser. Fax software was an earlier attempt to do the same thing. That is, let you send and receive faxes without having a separate stand-alone fax machine. The software runs on your PC and monitors the telephone line for fax tones or grabs the line to send a fax. That can be a problem when you are on broadband and nowhere near a phone line or using your only phone line for Internet access.

The new generation of Internet faxing does away with the phone line, at least on your end. The other party might have a fax machine or fax software, or they might also be using an Internet fax service. Here's how it works.

To send a fax, you compose your fax message using whatever text editor or word processing program you have on your computer and then attach it to an email message. You send the email to the phone number of the intended recipient at the Internet fax service provider. The provider's system converts your attachment to the fax format and then sends it out as audible tones over a phone line to the number you specified. In essence, the system emulates a real fax machine.

Another option is to use a form on the Internet fax service's website to compose and send your message. The receiving party won't know how you created your fax message. It could have come via machine, software, email or web based fax.

To receive a fax, you tell the sending party the phone number that the Internet fax service has assigned to you. They send the fax on their machine to that number. The service provider then converts that incoming fax to an image file and attaches it to an email that is sent to you. You open the attachment and read the fax message on your computer screen. You can then print it off if you want a hard copy, but I'll bet you won't opt for that awful thermal paper that fades with age.

The ability to send and receive faxes online frees you from being tied to a phone line or a fixed location fax machine. Even the small machines aren't all that portable for business trips and there's no phone jack at the coffee shop. It's much easier to pick up your emailed faxes while sipping a latte at your favorite WiFi hotspot. On business trips, you aren't stuck waiting at the hotel for a fax to arrive on their machine. Your incoming faxes will find you the next time you check your email.

Since computers are used to generate most of the faxes, it makes sense to eliminate the paper step and make use of the versatility of Internet transmission for the majority of your fax communication needs.

Find out how to get a fax number that sends and receives faxes using your current email address. Try eFax free – instant activation.

When Switched Long Distance Service is Best

So what's the best phone service for a small or medium size business? Do you buy everything from the local phone company, go with a competitive provider's "bundled" plan, have separate local and long distance services, or scrap everything and jump into VoIP?

The right answer is the one that gives you the lowest total phone bill with the voice quality and reliability you need to effectively conduct business. But which option is the right one? In many cases the a la carte approach will save you the most money. Here's why.

Your local phone company has the competitive advantage for providing dial tone and local phone service. It's no accident, it's the law. The local carrier, also called the ILEC or Incumbent Local Exchange Carrier, basically owns the rights to the copper wires that run to your location. Other companies can use those wires, but they have to lease them at some profit to the ILEC. Your local phone company gives you reliable dial tone service at a decent price.

What your local carrier doesn't own is exclusive rights to the long distance lines that run from phone company to phone company. These are provided by Inter eXchange Carriers or IXCs. AT&T was the original provider of this service, but deregulation has encouraged competitive providers for the last 20 years or so. You have the right to select which long distance carrier handles your state to state and in-state long distance calls, and nearby long distance calls that are also called Intralata or local long distance.

Your local phone company would like you to buy a bundle of both local and long distance service from them. That gives you the convenience of a single phone bill, but usually at quite a price. You are almost always better off keeping your local and long distance phone bills separate.

One competitive long distance carrier we like to recommend is PowerNet Global or PNG. They are a well established company with a good reputation for service. PNG has long distance plans that range from 3.9 cents per minute to 4.5 cents per minute anytime day or night. You would choose the 4.5 cent plan if most of your calls are local and you rarely use $15 worth of long distance calls per month. With this plan there is no monthly fee for low volume usage. The 3.9 cent per minute plan also has no monthly fee if your usage is over $15. Otherwise there is a $2.50 per month billing fee.

If these rates sound good, you can learn more and order PowerNet Global long distance service online. PNG can also help you transfer your toll free numbers and get you new calling cards for travel.

So far, I'm assuming that your office has less than a dozen actual phone lines which may or may not be shared. Once you get big enough to have a dozen or more lines, you'll probably save more by switching to T1 digital line service. This combines up to 24 local and/or long distance lines on a digital line service that can interface with many PBX telephone systems. You can check T1 line prices and get T1 sales help through T1 Rex.

VoIP? It's the hot new technology but isn't necessarily a cost saver now that switched circuit rates have been so dramatically reduced over the last few years. Large enterprises that are building new facilities from the ground up are the best candidates for VoIP telephony.

Business Long Distance Rates Search Tool

Are you sure that you are getting the best long distance phone rates for your business? REALLY sure? Here's a long distance rate finder for business lines that will give you a chart of competitive pricing in seconds. Go ahead, give it a try.

EV-DO Gives You Broadband Internet On The Go

WiFi Hotspots are great when you need online access away from the office. But what do you do when there is no nearby hotspot or you want to access your order entry or website at a client's place of business? EV-DO is a wireless broadband option that can give you download speeds up to 2.4 Mbps and is available in many major cities.

EV-DO or EVDO stands for Evolution Data Only or Evolution Data Optimized. Evolved from what? Actually, evolved from a more established standard called 1xRTT or single carrier Radio Transmission Technology. Both are in a family of wireless data services for cellular phone systems called CDMA 2000. CDMA stands for Code Division Multiple Access, a cellular technology that is popular in the United States.

The idea behind CDMA 2000 is that a cell phone service that is already digital can also deliver Internet data packets using the same transmitters and cell towers. That enables Internet services for cell phones but also stand-alone wireless Internet service for laptop computers. That's right. Your computer can get lower or higher speed broadband Internet service through a cell phone service without using the voice aspect of cellular.

1xRTT and 1xEV-DO are always-on Internet services. To access them on your computer, you'll need a plug-in adaptor like the Audiovox PC5220 Air Card or the Novatel V620 EV-DO PC Air Card. You plug it into a Type II PCMCIA slot on the side of your computer and flip up the little antenna (on the Audiovox).

The 1xRTT is also known as NationalAccess because it is widely available on both the Sprint and Verizon cellular networks. Maximum speed is 144 Kbps and with typical speeds of 70 to 80 Kbps. That's easily two to three times what you'll get with dial-up Internet access. It'll probably be just what you need for email and simple web usage and it's available just about anywhere your cell phone works.

1xEV-DO is the "evolution" or upgraded service for CDMA cellular networks. It uses all of a single 1.25 MHz cellular channel for data service. EV-DO runs at a maximum download speed of 2.4 Mbps and typically 400 to 800 Kbps. That's as good as you'll get from many DSL and Cable Internet services with the extra advantage of mobility. Verizon is the primary provider of EV-DO with service in 32 cities including:

Atlanta, GA
Austin, TX
Baltimore, MD
Boston, MA
Chicago, IL
Cincinnati, OH
Columbus, OH
Dallas/Fort Worth, TX
Dayton, OH
Hartford, CT
Houston, TX
Jacksonville, FL
Kansas City, MO
Las Vegas, NV
Los Angeles, CA
Madison, WI
Miami/Fort Lauderdale, FL
Milwaukee, WI
New Haven, CT
New Orleans, LA
New York, NY
Newark, NJ
Orlando, FL
Philadelphia, PA
Phoenix, AZ
Pittsburgh, PA
Providence, RI
San Diego, CA
St. Petersburg/West Palm Beach, FL
Tampa, FL
Washington, DC

EV-DO is perfect for road warriors who travel to these major US cities or for anyone living in those service areas who wants a wireless high speed Internet service.

You can also view all of the cellular phone and cellular data offers we have available by visiting Cell Phone Plans Finder and browsing through the services and available phones. Please note that these offers are subject to change at any time. If you want one of these special offers, order now.

Stratellites are Starting to Fly

The first Sanswire Stratellite lifted off the ground this month, symbolically launching the new age of airships. Only this time the airships are automated communications platforms, as I wrote in "Your Next ISP is a Blimp."

Like the great airships of the 1930s, the Stratellites are whales of the sky. The prototype "Sanswire One" is 188 feet long and shaped like a double-wide dirigible. It is a dirigible. The skeleton is a thin frame of high strength aluminum. The skin is a light colored Dupont Tedlar, a polyvinyl fluoride film that clings tightly to protect the innards of the craft. Inside are helium lift cells and the communications gear that makes the Stratellite a wireless repeater for broadband Internet, including VoIP, and perhaps cellular telephone and video transmission.

This first lifting test of the Stratellite is part of the engineering program that will lead to production models that will be 450 to 800 feet in length and carry several thousand pounds of microwave transceivers. They'll be powered by an array of thin flexible solar cells that cover the top of the ship and generate 10 KW of power. Unlike the passenger carrying dirigibles, Stratellites are autonomous robotic vehicles that climb to an altitude of 65,000 feet and hover over a fixed point above the weather and aircraft lanes. A GPS navigation system directs a cluster of electric ducted fan thrusters to keep each airship at its designated station.

So why a technology from the early days of flight when we're in the satellite era? Satellites turn out to be very expensive to build and launch and are basically throw-away items. LEO or low earth orbit constellations need dozens or hundreds of satellites because they are constantly moving in their orbits. Geosynchronous satellites are so far away from Earth that the latency due to the speed of light makes them generally unsuited to two-way voice communications. But park a reusable airship in the stratosphere just 13 miles up and you have a communications platform that can cover a 200 mile radius in all directions. It's estimated that 300 Stratellites, built and launched at a cost of about a tenth the cost of satellites, could easily provide blanket broadband coverage to the entire United States.

But broadband is only the initial justification for a Stratellite fleet. The same vehicles can be used as cellular towers in the sky to cover remote areas, dead zones and perhaps even cities that are just tired of so many steel towers popping up. They'll also be ideal for wide area paging and text messaging.

The next step is a flight test that is now going through the approval process with the FAA and Air Force so that Stratellite One can lift off from Palmdale, California and be tested at Edwards Air Force Base nearby. Hopefully that will happen sometime this summer. Following a successful flight test program, production will begin early in 2006 ramping up to 300 vehicles per year by 2007.

In addition to U.S. based telecom services, Stratellites have a built-in demand worldwide. GlobeTel, the parent company of Sanswire Networks LLC, is reported to have an agreement to provide Stratellites for broadband, VoIP and video to South America, starting with Lima, Peru. They'd also be perfect for the huge landmass of Asia and the extensive island archipelago of Indonesia.

If you have a current need for wired digital business lines from T1 through Optical Fiber, get an up to date price quote from T1 Rex.

How T1 Works in Rural Areas

T1 dedicated voice and data lines are available just about everywhere in the U.S. That may come as a surprise if you run a ranch or farm, or are just located in a more rural area and have tried to get DSL, cable or wireless Internet service. The oldest digital technology is also the most prolific.

The reason for this goes back to why T1 line service was invented in the first place. In the beginning it was never intended to be a stand-alone service sold to businesses. Back in the 1950s telephone companies needed an efficient and reliable way to carry lots of phone calls between their switching offices. Bell Labs came up with a standardized digital trunking system that could carry 24 phone calls on two pair of copper wires. What's more, these T1 lines could carry phone calls as far as needed with no loss in quality.

The quality issue is important. If you remember making long distance phone calls back in the 1950s and 60s, you also remember how noisy they were. Often you could even hear faint conversations in the background which was called crosstalk. Such was the nature of analog carrier telephony. Today, all long distance calls are digitized and it's not unusual for the party you are talking to on the other side of the ocean to sound like they are right next door.

The reason this is possible is that digital signals are made up of numbers consisting of zeros and ones. When an analog signal degrades over distance, the noise and crosstalk that are picked up are indistinguishable from the original signal. The longer it travels and the more amplifiers it gets boosted through, the more the conversation degrades. Digital signals degrade too. They pick up noise and crosstalk the same as analog signals. However, because we know that a digital bit is either a one or a zero, we can rebuild the noisy signal good as new.

The device that does this is called a regenerative repeater, sometimes shortened to just repeater or regenerator. The regenerative repeater is not just a simple amplifier. It actually rebuilds the signal back to original specifications. You can't tell by looking if the signal from the regenerator is the original or an exact duplicate. That's the beauty of digital.

These regenerative repeaters need to be placed every 6,000 feet or a little over a mile apart. By doing so, T1 lines can be carried far out into the countryside. You may get T1 service running perfectly at 1.5 Mbps upload and download even 20 miles or more from the nearest telephone office.

T1 lines can carry broadband Internet service or multi-line telephone service. In some areas, the same line can carry a mixture of the two. Or you can use the broadband Internet access for VoIP telephone service. Either way, if you have standard landline telephone service to your location, chances are that you can also get T1 digital service.

If you have a business that would benefit from high speed digital line service, let our technical team at T1 Rex give you a quick quote on T1 line services. Use our T1 instant online quote form for service.

PAN, LAN, MAN, WAN

The world of computer networking is filled with acronyms and these four happen to be in order. Can you guess how?

OK, that's pretty easy. It's by distance from near to far. The only one of these that hasn't been around for ages is PAN or Personal Area Network. PANs include Bluetooth, USB, UWB (Ultra Wide Band) and FireWire. A personal area network is intended for your personal use to interconnect electronic devices you are using. Bluetooth is emerging as the king of wireless personal area networks. If your cell phone and laptop computer both have Bluetooth enabled, you can get Internet access for your computer via Bluetooth from your cell phone that is connected to an EV-DO or GPRS data network.

Most everybody has a LAN or Local Area Network now. There once were many protocols for connecting computers, printers, and telecommunications networks within the corporate environment. Eventually everyone migrated to Ethernet with TCP/IP. That has gelled to the point where every new technology had better have IP connectivity, at least at the edges. The standardization around the Internet Protocol and Ethernet has promoted an economy of scale to the point where you can buy a 10/100 Mbps Network Interface Card at Wal-Mart for under ten bucks.

Every PC and many printers now come with Ethernet ports standard. Most portable devices support the Wireless version of Ethernet, Wi-Fi, which is also termed a Local Area Network. A LAN is intended for use within a room, building or area. WiFi's range of around 300 ft. puts it into this category.

Within an office or corporate campus, networking revolves around the LAN or LANs running on CAT5, CAT5e or CAT6 copper wiring with some spans of fiber optic cable and some wireless LANs. When you leave the LAN, you enter the world of MANs and WANs.

MAN is Metropolitan Area Network. It's intended for use within a city. A typical example is a SONET Synchronous Optical Network that is set up as a pair of fiber optic rings within the business district of a city. The reason for a pair is to provide redundancy in case one of the rings fail. The other takes over within 50 msec, perhaps so fast the outage isn't even noticed by many users. You get to the MAN with an access network connection. That may be an OC3 or OC12 fiber optic link or a T1 or T3 service.

Note that SONET is a different protocol than Ethernet. With some fancy bit handling, Ethernet can be formatted to be carried by SONET, T1, T3, or other digital networks. The Ethernet packets can be split up to fit the requirements of the carrier and reassembled at the other end.

Going cross-country you are using a long distance carrier called a WAN or Wide Area Network. A WAN can connect MANs together or simply connect a group of individual locations. The Internet is an enormous WAN. You can get WAN service from a variety of competitive carriers with speeds from T1 at 1.5 Mbps up to OC48 at 2.5 Gbps or even OC192 at nearly 10 Gbps.

Most WANs are TDM or Time Division Multiplexing based because that is the standard adopted by the telephone carriers that first implemented them. Since much data is now packet based using the IP standard, carriers are now offering native IP based networking connections in many areas. That means that your LAN data never changes protocol. It leaves your router as Ethernet, traverses an Ethernet WAN, and hooks to another LAN some distance away. To the IT manager it all looks like one big corporate LAN, even though a common carrier provides the link between sites.

GigaPackets is our service to help you get the best pricing on the T1 through Fiber Optic Network Connections you need. Our team of technical consultants will be happy to discuss your MAN and WAN networking requirements at any time.

T3 Internet

Dedicated Internet service gives you a private high speed line from your company to the Internet. This is important because many always-on Internet connections have a bandwidth that varies widely depending on how many other users are sharing the service. That's right. DSL, cable and wireless Internet services are priced based on statistical multiplexing. In other words, they are sold to many more users than would be able to get a broadband connection if they were all on at the same time. This is called oversubscription.

So, wait a second. You've got broadband but it really isn't broadband? Actually, you probably will get something of a broadband connection much of the time. But it's not guaranteed. The statistical part of the statistical multiplexing is based on the fact that, statistically speaking, everyone isn't uploading or downloading at the same time.

You'll likely take advantage of this phenomena in your own company. Look around. How many people are actively typing on their computers at the same time? How many are even at their desk? You don't need to allocate a Mbps full time for each employee. If you've got a dozen to maybe two dozen people who need internet access, a T1 line at 1.5 Mbps might be all you need. At any given time, a user might think they have the line all to themselves. That may well be true for the fraction of a second they are loading a new page.

The reason you want dedicated Internet access is that YOU want to be able to control your bandwidth usage. That dedicated line may also be used for a web site server and an email server. Overnight, when everybody is gone, the entire bandwidth can be used for offsite backup of computer files. In a pinch you can commandeer the line or a given amount of bandwidth for a particular need, such as downloading engineering drawings to a supplier. It's also essential to manage your bandwidth if you are using VoIP telephone in place of standard switched telephone service.

When T1 Internet access isn't adequate, T3 Internet will give you a massive jump in available bandwidth. T3 line speed is 45 Mbps. That's fast enough to be the backbone for many smaller Internet Service Providers. It's also adequate as the Internet service for companies with hundreds to maybe a thousand employees. For smaller operations, T3 Internet will give you the ability to run hosted VoIP service, perform faster backups and disaster recovery, host video conferences with full motion, rapidly transmit large engineering files or some combination of these.

T3 Internet may be referred to as DS3 Internet service. That's because DS3 is the digital signal level that runs on a T3 line. DS3 may also be delivered via fiber optic cable rather than coaxial copper cable.

If you are interested in T3 Internet service for your high bandwidth business applications, get a complementary T3 Internet Service Quote from Telexplainer.

Getting From Point to Point

Businesses with multiple locations need a way to network their far flung operations. Within a corporate campus or industrial park, you can often use copper pairs, fiber optic cable, wireless or free space optical transmission. But if your corporate office is in one city and you have dozens, hundreds or thousands of retail locations across the country or around the world, you need a long haul infrastructure.

A popular connection is the dedicated T1 point to point line service. It's called dedicated because it is 100% dedicated to your communications. No one else uses the line, which helps keep your information secure. It's also always available. You lease the line facilities with a monthly charge on a 1, 2 or 3 year contract and it's your private connection.

What can you use your T1 point to point service for? Just about anything that can be digitized and will fit within the bandwidth of the circuit. T1 is bi-directional with 1.5 Mbps of bandwidth in each direction. That makes it suitable for carrying traditional PBX based telephone calls, VoIP telephone, broadcast quality stereo audio, surveillance video, video conferencing, medical imaging and telemedicine, remote instruction, sales and accounting data, computer aided drawings and manufacturing instructions.

If you need additional bandwidth you can "bond" T1 lines together to get two times, four times, up to six times the bandwidth or 9 Mbps. Above that, it makes sense to move up to the next higher grade of service which is T3, also known as DS3 line service. That runs at 45 Mbps and is capable of carrying broadcast quality video with some compression.

If you need reliable connections between locations but not on a full time basis, frame relay service may be more cost effective. Each of your locations connects to the frame relay network, which sets up virtual connections from point to point. Other people also use the network, so you buy a committed information rate or CIR which guarantees your packets reliable transport when you need it.

The least expensive option is to use DSL or T1 connections from each location to the public Internet. You can set up a VPN or virtual private network using encryption software to protect the privacy of your data. It's possible to get connected to the Internet from just about anywhere and you can add locations at will. You are only subject to the vagaries of the Internet, which is a "best effort" service rather than guaranteed performance.

Trying to decide how best to interconnect your business locations? Talk it over with one of our technical experts, who will recommend the best options for your particular needs. Visit MegaTrunks now for a complementary consultation on point to point dedicated lines.

What's The Difference Between DSL and T1?

Digital is digital, right? If so, then there really isn't any big difference between DSL and T1 lines, is there?

Actually there is quite a bit of difference, but there are also similarities. You can get always-on Internet access on both a DSL line and a T1 line. T1 lines download at 1.5 Mbps. DSL may also be that fast. You can use either with your VoIP telephone adaptor. So why would you spend ten times as much for a T1 line as you would to get DSL?

The answer is that there's digital and then there's digital. Digital line services come in many flavors and the each have their advantages and disadvantages.

Take DSL for instance. When you think about getting a DSL line for under $50 a month, what you are thinking of is residential DSL service that is technically called ADSL or asymmetrical Digital Subscriber Line. The asymmetrical part means that upload and download speeds are different. The reasoning is that most Internet users need fast download speeds for web browsing, but can live with lower upload speeds for sending email, typing in web addresses, filling out forms, etc. You might get 1.5 Mbps download but 128, 256 or 384 Kbps upload speed. There is a symmetrical type of DSL service with the same upload and download speed, but that is usually sold to businesses at a higher price.

T1 is based on a different technology, although both T1 and DSL are digital lines. T1 is a synchronous time division multiplexed system, meaning that it is not only on all the time, but it is sending something all the time and expecting to receive something all the time. That something might be no more than framing bits to keep both ends of the connection synchronized to define the individual time slots. That is not really important for Internet access, but does allow T1 lines to carry standard switched telephone calls as well as VoIP phone. T1 can carry 24 telephone lines to support a business PBX system. Each phone call occupies a well defined time slot in the T1 transmission.

T1 is also symmetrical. That means that the download speed is 1.5 Mbps and the upload speed is 1.5 Mbps. That synchronized line speed never varies and it doesn't matter how far you are from the phone company office. It's always 1.5 Mbps. DSL on the other hand, uses a Discrete Multitone Modulation (DMT) technology that adapts itself to the condition of the telephone line it shares. The speed you get depends on how far away you are from the equipment providing the DSL service, and the amount of noise and interference on the line. The closer you are, the higher your line speed. If you are more than a few miles away, you may not be able to get DSL at all. Just about everyone can get T1 service installed, but the cost goes up as you get more and more remote.

The other difference between DSL and T1 is not technical. It is in the commitment to availability of the service. T1 lines come with a Service Level Agreement or SLA that provides compensation for outages. DSL is a "best effort" service. That doesn't mean DSL is inherently unreliable, but if there is an outage then T1 with its SLA gets the highest level of attention.

So, why would you buy one service over the other? For residential use, DSL provided on your phone line or cable Internet service provided by the local Cable TV company give you very good Internet broadband service at a reasonable price. Businesses might choose business grade DSL if their need is fairly light Internet access or running a free WiFi hotspot.

But if full-time Internet access is key to your business or if you plan on running VoIP telephones or standard switched telephones using a PBX system, T1 is really what you need. T1 lines can also be set up as dedicated point to point connections between business locations. Granted, T1 prices are 8X to 10X what you'll pay for DSL. But that's still reasonable as a dependable digital lifeline for most medium and even small businesses.

If you need broadband voice, data, or Internet access for business applications, let our T1 consultants help you get the right service at the lowest price.

What's The Difference Between T1 and POTS?

T1 and POTS are both telephone services. In one way, they work the same. You pick up your phone handset and you hear dial tone. You then dial the number you want. If your business has a PBX telephone system, you'll probably have to dial a number such as "9" to get an outside line. But that's got nothing to do with the type of phone line you are using. It's simply so that outside lines can be shared, since you don't really need a hundred lines for a hundred employees unless everyone is living on the telephone.

Let's start with POTS. It's an acronym that stands for Plain Old Telephone Service. I'm sure that whoever came up that scientific term thought long and hard about it. POTS really is a good term because everybody can nod in agreement about what a POTS line is. Plain old telephone service is that pair of copper wires that connects to a standard telephone and provides power to the phone, a ringing signal when calls come in and connectivity to the phone company central switching system.

A POTS line, usually just called a phone line, can hook directly to a standard analog telephone. It can be one of several lines that you select with a key telephone system or it can connect directly to a PBX phone system. With POTS you can get local and long distance service, Caller ID and other calling features. POTS lines are also used for dial-up computer access using modems and they connect directly to alarm systems for central monitoring.

T1 can be thought of as a digital carrier for POTS lines. You can't plug a T1 line into a regular telephone set. But you can plug a T1 line into a T1 interface card in a PBX system. When you do that, the PBX can use the T1 line in place of up to 24 POTS telephone lines. You'll never notice the difference, other than perhaps the phone bill. The advantage of T1 is that it's cheaper to bundle all those individual phone wires into a single digital line that runs between your office and the phone company. The price advantage usually comes at 8 to 12 phone lines, although it might make sense for fewer lines if you do extensive long distance calling or want to split your T1 line into 12 phone lines plus broadband Internet service.

Because T1 is a digital service, it can carry both digitized telephone and/or Internet data. It can also carry other things like broadcast audio and surveillance video. T1 lines come in a variety of flavors. You can get inbound and/or outbound calling, local and/or long distance service, voice and/or data. Long distance rates are very attractive if you can commit to thousands or tens of thousands of minutes per month or more. A specialized form of T1 called T1 PRI or Primary Rate Interface is used by call centers. It provides 23 telephone lines plus Caller ID and Automatic Number Identification data.

If you currently have more than half a dozen phone lines or need digital connectivity for your business, you should let one of our technical consultants explain the various options available for your business and what each costs. You might just be able to save a bundle on your monthly phone bill with service that is as good or even better than what you have now. Simply enter a request for a T1 quote at T1 Rex.

Virtual Calling Cards Make Sense For Business

You probably carry one or more telephone calling cards in your wallet. They can save you a bundle if you make long distance calls from hotel rooms, pay phones, or client locations. One of the best cards you can have is called the "virtual" calling card. You may not have heard of it until now, but there are a lot of advantages to going virtual.

So, what is a virtual calling card and why would you want one instead of a regular phone card? It's called virtual because there is no physical card delivered. That seems different than buying a prepaid card off the rack at a drugstore or using the plastic card from your long distance company. Actually, you use a virtual card much like any other calling card. To make phone calls you dial a toll free access number. The system will ask you to enter your access code which includes your PIN number. Then you enter the number you want to call.

The big advantage to virtual calling cards is that they have truly low per minute rates. For instance, the popular CogniCall calling card offers 6.9 cents per minute for calls in the 48 US states. That's probably a lot lower that what you'd be billed if you use the card that comes from your long distance carrier. It doesn't seem as low as those colorful prepaid cards that advertise 1.9 or 2.9 cents a minute. But use one of those for awhile as see how many minutes you really get. They often charge "connect" fees for each call you make. Plus once you start using the card, the minutes start expiring if you don't use them all at once. After a few months your unused minutes have vaporized and you wind up paying a buck a minute for the one phone call you made.

Another thing to be aware of is the billing increment. Many calling cards charge in 1 minute or more increments. The time you call is rounded up to the next minute. CogniCall bills in 6 second increments with a 1 minute minimum. This smaller billing increment saves you money on each call and becomes really significant if you make a lot of calls.

The CogniCall card is called postpaid instead of prepaid. That's another way of saying billable. Your calls are charged to your credit card in the months that you make calls. If you don't make any calls, you don't pay anything. Minutes don't expire because you don't have a total number of minutes. You pay as you go.

Do you travel internationally? Most cards only work in one country. If you want to make calls overseas, you need a calling card that offers international origination. CogniCall lets you originate calls in over 50 countries by dialing toll free access numbers where you happen to be. That lets you avoid the monstrous phone bills you get stuck with if you make international calls from hotel rooms. If you stay with someone or visit a business client, you can make calls without running up their phone bill.

As of this writing, you can call the US from Germany for 8.7 cents a minute, from the U.K. for 11.6 cents a minute, from India for 32.3 cents a minute, from Mexico for 33.4 cents a minute, and from China for 59.5 cents a minute. Calls originating in the US cost generally less.

Another advantage of a virtual calling card is that you can get it quickly. You order CogniCall online anytime and you'll get an email confirmation. Then you call their office during business hours to confirm your account and they send you your access code and dialing instructions by email. You'll also have access to a website to monitor your account and get the access numbers you need for places you are going to visit. You can often get your virtual calling card the same business day if you forget to order until the last minute before a trip. Best to allow yourself a day or two, though.

There is no charge to order a CogniCall virtual calling card. You pay nothing until you use it and then you only pay for the calls you make. If you travel on business or vacation, it makes sense to have one of these handy just in case you ever need it. If you make a lot of calls away from home, you might save a small fortune. Find rates and get an international calling card now.

What's The Difference Between DS1 and T1?

T1 lines are becoming ubiquitous for business digital connections. T1 phone lines replace up to 24 standard telephone lines in one digital trunk line. T1 Internet service gives you 1.5 Mbps bandwidth both upload and download. You can even combine the two with T1 Integrated line service that allocates part of your T1 line for telephone voice circuits and part for Internet data. So, then, what should you order? Is it a T1 line or DS1 service?

DS1? Where did that come from? Is DS1 a better or worse choice than T1? What's the difference between DS1 and T1 anyway?

Relax. In colloquial terms, DS1 and T1 mean the same thing. There is a very fine point of technical difference between the two. You can get DS1 service without a T1 line but if you have a T1 line, you've got DS1.

DS1 is a digital signal level that is part of a standardized hierarchy or building blocks of digital services for TDM (Time Division Multiplexing) digital lines. A DS1 is a DS1 regardless of whether it is delivered on a T1 line, a microwave relay, a T3 line or a fiber optic carrier.

Actually it all starts at the bottom with DS0. DS0 is the bandwidth you need to transmit one digitized telephone call using the legacy telephone standard for PCM or Pulse Code Modulation. It's an 8 bit channel transmitted at 8 Kbps or a total of 64 Kbps. That's the gold standard for "toll quality" voice. That same channel can also be used to carry 64 Kbps of data rather than a telephone call. The data bits might represent a dial-up modem connection, a portion of a broadband Internet service, a portion of an Ethernet signal, a small portion of a video transmission, or signaling and Caller ID information to support a call center.

A T1 line multiplexes or aggregates 24 of these DS0 channels into a DS1 with a total bandwidth of 1.536 Mbps. But a T1 line runs at 1.544 Mbps. What's missing? The extra 8 Kbps represents the framing bit that T1 adds to each group of 24 DS0 channels so that the CSU or channel service unit at the other end of the line knows where to demultiplex the frame of 24 DS0s. With synchronous lines such as T1, framing bits are needed to keep the sending and receiving ends tightly synchronized.

Remember that most people will associate DS1 with T1 and that's normally how you would get DS1 service. If you needed a lot more bandwidth, you might order DS3 service that would be delivered on a T3 line. DS3 is the equivalent of 28 DS1s. A DS1 service might be separated from a higher speed service using an add/drop multiplexer. For instance, an OC3 fiber optic carrier can deliver 3 DS3 services or 84 DS1 services or 2,016 DS0 channels. Because they are all constructed according to the rules of the same digital signal hierarchy, you can multiplex and demultiplex these signals at will.

Get the best DS1 and T1 line prices from T1 Rex. We can also get you excellent T3 line pricing through T3 Rex and low OC3 prices from Gigapackets. Our team of technical experts will respond to your inquiry on any of these services.

GPRS Enables Cellular Internet

A popular wireless Internet technology is GPRS or General Packet Radio System. Unlike WiFi, GPRS shares cell phone channels. GPRS is an add-on to the GSM or Global System for Mobile Communications cellular standard. GSM systems that include GPRS can carry both telephone calls and internet data, with some phones being able to do both at once.

GPRS was invented as part of the move to what is called 3G or 3rd generation cellular phone service. That's the idea that cell phones can also be computers, email and web browsers and even TV receivers. It's a tall order for a technology that was originally designed to simply make telephones mobile.

So, how does GPRS work? It uses the idle radio capacity in GSM telephone systems. All cell phone systems have capacity that isn't being used except when everybody is on the phone in a particular cell. Normally that idle capacity wouldn't be doing anything. It would simply be held in reserve for the next callers. What GPRS does is to use that extra capacity to create a data network. If the system gets really busy with telephone calls, then the data gets a lower priority and data rates slow down.

GSM is the most popular cellular technology in the world with over a billion subscribers in 85 countries. It's based on TDMA or Time Division Multiple Access. GSM channels are 200 KHz wide and divided into 8 time slots. Each slot can carry a digital telephone call coded at 13 Kbps or 14.4 Kbps of IP or Internet Protocol data. Busy cells may use multiple channels to support the call demand.

If you could use an entire GSM channel to carry data, you could have a bandwidth of over 100 Kbps. With compression, the maximum bandwidth for GPRS is 170 Kbps. Don't get your heart set on that rate. GPRS is set up on a class system, with class 8 being the default. Class 8 is known as 4+1. You get 4 time slots for download and 1 for upload. Another popular class is GPRS class 10, also known as 4+2. That's 4 time slots for download and 2 for upload.

Typical download rates might be on the order of 40 Kbps or so. That's not the blazing speed of broadband but is plenty for SMS messaging, email, order entry and web browsing. Laptop computers can also access the Internet through GPRS with an adaptor. T-Mobile offers the Sony Ericsson GC79 PC Cellular Card that has both GPRS and WiFi capability. Within a WiFi hotspot you get the speed of WiFi. Elsewhere, within the coverage of the T-Mobile GSM cellular network, you use GPRS. This can be the perfect combination for mobile business people who need access to their Internet based tools while visiting clients.

What are the hottest cell phone deals available right now, including free cell phones and wireless modem aircards? Use the Cell Phone Plan Finder to check out the top phones and associated wireless service plans.

What's Inside Intel's New WiMAX Chip

Intel has just announced availability of its first WiMAX product, the PRO/Wireless 5116 broadband interface. This long anticipated chip, code named "Rosedale" during development, is a complete WiMAX system on a 360 pin integrated circuit. With this chip and a relatively few external parts, it's possible to build WiMAX modems and residential gateways. The technology and marketing power of Intel ensure that WiMAX wireless broadband service is clearly imminent.

WiMAX or Worldwide Interoperability for Microwave Access is the coming 800 lb Wireless Gorilla. Instead of a mere few hundred feet of WiFi hotspot coverage, WiMAX will create giant coverage areas with a range up to 31 miles in all directions. WiMAX is to WiFi as cellular telephone service is to cordless home phones.

The new Intel PRO/Wireless 5116 broadband interface meets the latest WiMAX specification, IEEE 802.16-2004, approved last July. This is essentially the first production version of WiMAX, although upgrades are in the works. You probably can't get WiMAX service yet unless you are part of the early implementations overseas. The Intel chip and others to follow are likely to change that within the next year or so.

So, what do those 360 pins connect to inside that little black chip? The answer is just about everything you need to create a WiMAX product. It's all digital, of course. There are multiple processors to do the math needed for generating the OFDM or Orthogonal Frequency Division Multiplexing radio signal and security encryption. A 10/100 Ethernet bridge provides one broadband interface. Another interface handles TDM (Time Division Multiplexing) circuits such a T1 or E1 lines. T1 is the most popular carrier grade digital line in the U.S. E1 is the basic carrier grade digital line in Europe. The output interface is the transmit and receive radio frequency signal that goes to circuitry connected to the antenna. There is also an external memory interface for connecting to SDRAM and FLASH memories.

The Intel Pro/Wireless 5116 broadband interface is essentially a very specialized computer on a chip. Designers need only to provide it with power, circuitry to complete the physical interfaces, and any specialized programming particular to a given application. The end products will be outdoor and indoor self-installable WiMAX modems and residential gateways for home and business use. The most popular application of WiMAX is expected to be wireless broadband Internet service. The Intel interface is also being billed as supporting TDM voice and real-time video and voice over IP.

Let T1 Rex find you better prices for T1 lines to support your business applications.

How DOCSIS Mixes Broadband With Cable TV

Cable modem service is hard to beat for residential and home office Internet users. It's reasonably priced at $45 a month or so. That's about what you'd pay for DSL and far less than the least expensive T1 lines. Of course, you can't run a server or provide Internet service beyond members of your household. But for most of us who just want to enjoy always-on Internet at broadband speeds up to 3 Mbps for personal use, it's a good price point. It can be even cheaper than dial-up when you want to have 2 or 3 computers online at the same time. When you factor in the cost of two dial-up services plus an extra phone line, cable Internet looks pretty reasonable. So, how does it work and what performance can you expect?

Like WiFi, broadband over cable is standardized. In this case, the organization is known as CableLabs or Cable Television Laboratories, Inc.. It was founded in 1988 as a nonprofit R&D consortium for the cable television industry. The major contribution of CableLabs is the DOCSIS specification. DOCSIS stands for Data Over Cable Service Interface Specifications. Your cable system will use one of the DOCSIS specifications and your cable modem will be certified to that level.

The original DOCSIS 1.0 specification became available in 1995. It's since been updated to DOCSIS 1.1 to include additional security and QoS Quality of Service features to support VoIP and interactive gaming. DOCSIS 2.0, the current specification, increased the upstream bandwidth. That's the bandwidth from your computer to the Internet. It is generally much less than the downstream bandwidth in both cable and DSL broadband services. The reason is that the pages and software you download are much larger than the keystrokes, email and occasional file transfers that you upload.

That asymmetrical bandwidth works well for mixing data with TV signals on cable systems. The upload channels are placed in the otherwise unused portion of the cable spectrum between 5 MHz and 42 MHz. Channel 2, the lowest broadcast frequency, uses 54 to 60 MHz. Upload bandwidth was originally 500 Kbps to 10 Mbps. DOCSIS 2.0 expanded that to 30 Mbps by using a more efficient modulation scheme and wider channels.

Now don't go getting too excited about the 30 Mbps. You don't get to use it all yourself. In fact, most cable companies limit upstream bandwidth to 128 or 256 Kbps. That's because that limited upstream bandwidth has to be shared with all the users on the system.

The same is true of the downstream bandwidth. Data is sent from the Internet through the cable system to your computer by making it look like any other TV channel. The cable system allocates one or more 6 MHz channels in the TV bands for broadband use. Each channel is capable of up to 36 Mbps of bandwidth. Once again, that bandwidth must be shared between all users. The data is framed using MPEG-2, just like satellite or digital cable television. A special program identifier or PID tells the cable modems that the signal on a particular channel is data not television. Of the 36 Mbps available, you'll likely get 600 Kbps to 3 Mbps at any given time.

At the cable head end, the CMTS or Cable Modem Termination System is responsible for slicing and dicing the Internet backbone connection among the cable modems on the system. There might be as many as a hundred to a thousand other broadband users sharing the backbone connection. A DS3 backbone can provide 45 Mbps, which is adequate for a single channel cable modem system. For larger systems, an OC3 connection running at 155 Mbps can handle several channels.

Cable modem technology is still evolving. CableLabs is working on the next upgrade, DOCSIS 3.0, to keep up with impending competition from fiber to the home and WiMax. DOCSIS 3.0 is likely to include channel bonding that would combine channels to increase bandwidth per customer from 10 Mbps to perhaps as high as 100 Mbps.

Video Transport On Digital Private Lines

High speed digital private lines, such as T1 and T3 carriers, got their start transporting telephone conversations. Over the last 20 years or so, businesses have pressed this technology into service to expand their local area networks and to tie their PBX telephone systems together. One more recent trend has been using digital networks to converge or combine data and VoIP telephone services. Another is transporting video signals.

The classic video standard is NTSC (National Television System Committee) which is what the U.S. adopted for over the air broadcast of black and white pictures in 1941. It has an analog bandwidth of 4.2 MHz and, with audio, is transmitted in a 6 MHz TV channel. Some clever engineering allowed color information to be squeezed into the same channel size.

Sixty some years later, most TV sets are still analog and still use the NTSC standard. But TV broadcasting is migrating to a new digital high definition standard, HDTV, and satellite and many cable TV signals are delivered digitally. They can then be used as digital inputs to high resolution monitors or converted to analog for monitors and TV sets that need that format.

One nice thing about digital video signals is that digital line services can be used to transport them between offices or cross-country. Digital video can be standard or HDTV broadcast programs, two-way video conferencing, medical imaging, security cameras and even digital cinema. Yes, it may not be that long before your local movie theaters ditch their massive film reels in favor of DVDs or even downloaded video streams stored on local hard disk drives.

The process of transmitting video digitally is quite a bit like what is done for digital telephony and digital broadcast audio. It all starts with a device called a CODEC or Coder/Decoder. This is the component that converts from analog to digital and back again. It also performs whatever compression is needed to fit the original signal through a particular size channel.

Why is that important? Raw digital conversions of analog signals can use up a lot of bandwidth fast. The standard telephone PCM (Pulse Code Modulation) codec called G.711 spits out a stream of 64 Kbps for each telephone conversation. Phone conversations are hardly what you'd call high fidelity. A real Hi-Fi stereo signal needs about 1.5 Mbps, which fits nicely on a T1 line. Video needs even more. A raw HDTV video signal needs 1.5 Gbps. That's 1,000 times what you need for audio. Even the standard NTSC video consumes about 143 Mbps. If video signals stayed in that format, you could forget transmitting them outside the studio or even recording them on DVDs.

The magic of the CODEC is compression of the converted signals. For video, the standard compression format is called MPEG (Motion Picture Experts Group) and the most popular format is MPEG-2. That's what's used for HDTV broadcasting and satellite TV. MPEG-2 does its magic by monitoring what is changing in the scene and only transmitting that. In practice, one frame of video doesn't really differ dramatically from the next, which comes only 1/60 of a second later. Get rid of all the "redundant" information in the pictures and the bandwidth requirement drops dramatically. That 1.5 Gbps raw HDTV becomes 19.4 Mbps for HDTV broadcast using MPEG-2 compression.

DS3 service running over a T3 line or multiplexed on a OC3 or higher optical carrier works well for transporting digital video signals using reasonable amounts of compression. A couple of HDTV signals will fit into the 45 Mbps bandwidth of DS3. Less compression can be used to transmit a single higher quality video stream for video production work, digital cinema or medical imaging use. If truly raw video is needed, OC3 at 155 Mbps, OC12 at 622 Mbps or OC48 at 2.488 Gbps are available. Otherwise, DS3 offers an excellent price point, wide availability, and enough bandwidth for most video applications.

If you'd like very competitive pricing for DS3 private line service for video transport or electronic data interchange, get the best deals now.

Understanding DS3 and T3

If you need a lot more bandwidth than the 1.5 Mbps delivered by a T1 line, it might be time to step up to DS3 service delivered on a T3 line. How much more bandwidth can you get? How about as much as 28 T1 lines or 45 Mbps? That's enough throughput for broadcast quality video transport, high volume call centers or Internet Service Provider backbones. If you have a really large organization, perhaps you want that 45 Mbps as YOUR Internet service connection.

So what is DS3 and how does it relate to T3? As you might guess, T3 and T1 lines are related. They were designed as part of family of digital network services for the telephone companies called the T-Carrier system. This isn't exactly new technology. The first T1 lines went into service in the late 1950s. What is new is the availability and reasonable pricing of T3 and DS3 services to non-telecom carrier businesses.

DS3 stands for Digital Signal level 3. That's the definition of the protocol that runs on the physical T3 line. DS3 is a TDM or Time Division Multiplexed synchronous format. It runs at 44.736 Mbps, which we usually call 45 Mbps for short. The transmission rate of 44.736 Mbps isn't some arbitrary number. It has to be that speed so that DS1 signals that are carried on T1 lines can also be carried on T3 lines.

There are actually two types of T3 circuits. The oldest is channelized T3 which is used to transport digitized telephone calls. Each channel is 64 Kbps wide and carries one phone call. A T1 line can carry 24 of these DS0 channels. A T3 line carries 672 of them or 28 DS1s. A device called an M13 Multiplexer combines the 28 DS1s and gets them aligned in the proper time slots to make a DS3, which can then be carried on a T3 line.

The other type of T3 format is called unchannelized T3. If you don't need all those little channels to support phone calls or modem connections, unchannelized T3 gives you one big data pipe with a payload rate of 44.210 Mbps. This is similar to an unchannelized T1 line but with a much higher bandwidth.

The physical connection from your equipment to the phone line Network Interface Unit consists of two 75 ohm coaxial cables with BNC connectors. That's different from a T1 line which gives you an RJ-48 jack at the NIU for use with unshielded twisted pair cable. One of the T3 coaxial cables is transmit, the other is receive. T3 is a full duplex circuit, meaning that transmit and receive are independent and both run at the 45 Mbps rate.

Outside your building the T3 line might stay as coaxial cable, but it is more likely to be carried on a fiber optic cable between your location and the carrier's office. It will likely be multiplexed onto a larger fiber optic carrier, even an OC48 or OC192, for long haul transmission.

But what if a T3 line has way more bandwidth than you need and a T1 line isn't nearly enough? In between, there are a number of options. If you need 3 to 9 Mbps your lowest cost option may well be to bond several T1 lines together to get the equivalent of a single larger circuit. Above that, fractional DS3 may be the better option until you need a full T3 or multiple T3 lines. Once you get to needing a 100 Mbps connection to carry your network traffic, OC3 or 100 Mbps Ethernet service on fiber optic cable makes sense.

Not sure what type of dedicated line service is most cost effective for your needs? Let our technical team explain the range of services available in your particular location and help you pick the digital service that best suits your applications.

HomePlug Gets The Jump On BPL

Powerline networking is already here, if you wish to take advantage of it. No, this isn't the Broadband over Power Line (BPL) that delivers Internet service to you using the electric company's high tension lines. This is local area BPL for use within a home or small office. The standard is called HomePlug 1.0.

The outside BPL has its issues with interference and cost. The inside BPL using HomePlug has none of those problems. It's affordable for individuals and small businesses and has been designed and tested to avoid interference to Ham Radio receivers. So how does HomePlug work and how can you use it?

HomePlug is the product of the HomePlug Powerline Alliance, an industry association that formed 5 years ago. The goal was to be able to use the normal power wiring within a house to function as an Ethernet-type data network. That goal seems more ambitious once you know some of the ugly things that are hanging around power lines just looking to cause trouble. You know those filtered surge protectors you buy to protect your valuable electronic equipment? HomePlug has to work in that environment without the filtering.

The allure of home power line networking is that its already in place. All houses, even those creaky hundred year old structures, are wired for 120 VAC power. Every room has at least one outlet and usually several. Why reinvent the wheel or, in this case, wiring when it's sitting there free for your use? With HomePlug, you simply plug an adaptor for Ethernet or USB into the nearest power outlet and connect your networked device. That could be a PC, printer, wireless access point and so on. The adaptors talk among themselves over the power wiring and act just like they were on their own network wiring.

HomePlug creates an Ethernet-like MAC (Media Access Control) layer with a throughput of 8.2 Mbps, which compares favorably with a 10 Mbps Ethernet speed of 9.8 Mbps and a 802.11b WiFi speed of 7.48 Mbps at the MAC layer. The physical layer for HomePlug has a throughput of 13.78 Mbps. No, these aren't 100 Mbps Fast Ethernet speeds, but they are likely more than adequate for most home office and small business networking.

HomePlug transmits on a frequency band of 4.5 to 21 MHz, which actually works much better than lower radio frequencies at crossing circuit breakers and bridging the two phases of typical residential 60 Hz power. This wide spectrum is generated using Orthogonal Frequency Division Multiplexing (OFDM) with up to 84 separate carriers. In actual use, some of the carriers have to be turned off due to interference from fluorescent lights, sparking motor brushes, switching power supplies in electronic equipment and light dimmers. Carriers that would interfere with Amateur Radio frequencies are also not used.

How about network security? You might think that it isn't an issue since the wires are in your walls. But there's another wire that leaves the house and connects at a power transformer outside, along with maybe 6 other houses. Yes, the power drop for your electrical service makes a convenient node for interconnecting multiple dwellings. Your HomePlug signals may well be sneaking into your neighbor's wiring. The solution is the same as for WiFi that radiates beyond your property. All devices on your network must share a common encryption key for 56 bit DES data encryption.

What Is Dedicated Internet Service?

We tend to put Internet connections into two categories. One is dial-up Internet service using a standard 56K modem. The other is broadband Internet delivered via DSL, cable modem, WiFi hotspot or wireless point to multipoint distribution. But how about a third alternative that is more reliable and faster than the others, perhaps with almost unlimited speed. That's dedicated Internet service.

But wait a second? My current Internet service is already dedicated, right? I mean, I'm the only one logging into it. Yeah, right. If you look at what's plugged into your modem and there's only one wire to your computer, your modem is indeed dedicated. Your internet service isn't by a long shot. Somewhere out of sight, probably at the local telephone, cable or wireless office, you are a mere one of many connected to the same Internet service. For DSL the device that divvies up the service is called a DSLAM or Digital Subscriber Line Access Multiplexer. The key word is Multiplexer. Any circuit that is multiplexed is shared.

The DSLAM at the telephone company office or its equivalent, the CMTS or Cable Modem Termination Service at the cable TV head end, takes a single broadband trunk line from an Internet Service Provider and splits out the bandwidth among dozens, hundreds or even thousands of customers. The theory behind this is that not all subscribers will be online at all times, even if the connection is always available. Most Internet users spend the majority of their time reading or writing email, looking at the web pages they have visited, and occasionally downloading software, music or streaming audio. While you're connection is idling, someone else can use the bandwidth to load another web page. In fact, during large parts of the day many computers will actually be shut off.

Now spread out this behavior over thousands of subscribers and you'll know statistically what the average bandwidth demand is. That's how big a line you should have to feed the DSLAM or CMTS. But broadband providers often oversubscribe their connections so that during busy times the connections can slow almost to dial-up speeds while in the wee hours you can get several megabits per second on download. If things bog down too much, the provider can always install a bigger pipe to the ISP.

Now, how would you like to have a direct connection from your router all the way to the Internet Service Provider? No DSLAM, no CMTS, no sharing. Well, you can share it within your office or with patrons of your business through a WiFi hotspot. But that's your choice. You're not at the whims of bandwidth hogs who are constantly downloading something or other or always streaming audio and even video at broadband rates. Yes, ISPs can oversubscribe their backbone connections to the actual Internet. The better ones will give you the bandwidth you are paying for.

The basic dedicated Internet service is delivered on a T1 line, a fractional T1 line or an even faster trunk. T1 runs at 1.5 Mbps, about the same as the advertised speeds for many DSL and cable Internet services. But since that 1.5 Mbps runs directly to the ISP, regardless of distance, it will generally perform both faster and more consistently than other broadband Internet services. A T1 line also comes with a service level agreement that results in more reliable service. If T1 isn't fast enough to support your organization's Internet access need or if you are transmitting high bandwidth video, you can step up to a T3 line at 45 Mbps or even an OC3 optical carrier at 155 Mbps. There are even faster connections, but you won't need them unless you are an Internet or applications service provider yourself.

Get a complimentary quote on T1 dedicated Internet service for serious business applications (T1 prices start at $200 to $400 a month) from Telexplainer.

You're Fibered!

What transmits data at gigabits per second from point to point using only a pencil-thin medium? Fiber optic cable, right? Yes, but a virtual fiber optic cable can work just as well and be a lot easier to install.

Virtual fiber? It's fiber optics sans fiber and sans optical frequencies. OK, it's radio waves. The millimeter wave bands of 70, 80, and 90 GHz were opened up for commercial use in 2003 by the FCC. Now GigaBeam has hooked up properties owned by none other than the legendary real estate developer Donald Trump with their product called WiFiber. Hey, there's an assignment for those "Apprentice" candidates. See who can beam together the most buildings in the Big Apple. The team with the most bandwidth wins, which is not a bad business metaphor anyway.

Millimeter waves are located in the EHF or Extremely High Frequency portion of the electromagnetic spectrum that extends from 30 GHz to 300 GHz. At those frequencies wavelengths are only a fraction of an inch. High gain antennas capable of forming tightly focused beams can be only a few feet in size.

That high gain is needed. At such short wavelengths, the signals tend to be absorbed by rain and even air. The 71 through 95 GHz frequencies are strategically located between two frequencies where oxygen more strongly attenuates radio waves, and below the submillimeter bands where water in the atmosphere makes it almost opaque. In the visible spectrum, fog is actually worse to penetrate than rain and can block Free Space Optical (FSO) beams that are also used as virtual fiber links.

You want a high gain antenna is to keep your radiated signal in as tight a beam as possible. The way antennas create gain is by focusing radio waves. A point source that radiates in all directions is called isotropic and has zero gain. But, take all the radio energy and send it out in a narrow beam and you've effectively boosted the signal in the beam direction just as if you had raised the transmitter power. Any spreading out of the signal to either side of the receiving antenna is essentially lost power.

Tight beams are also valuable for point to point communication because they don't generate interference to others and they are hard to intercept. Unless you are directly in the path of a millimeter wave signal you won't even know it is there. Millimeter wave transmissions can be focused into beams only 1 degree wide and 1 to 4 miles long. That works out well for secure links between buildings. Beyond the signal range, another system can be operating on the same channel without interference or detection. Off to either side, other millimeter wave beams on the same channel can serve other buildings in the same metro area. The radio signals can also be encrypted to further enhance security.

So what is Donald Trump doing with all that connectivity? It's to provide residents at Trump Place in New York City with high speed wired and wireless data service, VoIP, video on demand and high definition television. In this case, it's virtual fiber to the home.

For wired fiber optic and copper WANs, let our GigaPackets service find you the best prices available for your application.

Asynchronous Pulsed Radiated Incident Light Communications

A naturally occurring form of meshed free space optical communications is now being considered as a model for "community" networking systems. Operating in the nanometer wavelengths far above the regulated spectrum, this transmission scheme is inherently license free, apparently not monetized as of yet, and requires only miniscule amounts of energy.

The protocol is Asynchronous Pulsed Radiated Incident Light communications. It falls into the category of UNB or Ultra Narrow Band modulation with a bit rate of only a few bps directly pulsing the lightwave emitter. While free-space optics (FSO) offer much higher bandwidths for extending networks between buildings over roadways and rivers, FSO technology is a point to point medium. Any meshing of network nodes requires multiple optical transceivers. Beyond a simple line of site cable replacement, system complexity and cost increases exponentially.

What's been needed to make optical mesh networks practical is a means whereby all nodes are within a direct line of sight from each other in three dimensions. Consider it a spherical communications space. Within that space, local network nodes self-organize much like Bluetooth networks. Each local net is known as a swarm. The swarm will stay locked in asynchronous communication as units join or leave the group.

The low signaling rate has the advantage of needing only a minimum amount of processing power and is highly immune to noise and interference. The individual pulsating yellow-orange light emitters are easy to track and distinguish within the swarm. Security coding is by mutual assent of the communicators, since any intruders can readily monitor all transmissions.

The IEEE has wasted no time in beginning the standardization process, designating the Asynchronous Pulsed Radiated Incident Light communications protocol with the name FiFli and establishing a FiFli forum to work out the details of 802.something-or-other. The initial standards draft will be designated as APRIL-1 although committee activity is so intense that there are expected to be 30 distinct APRIL versions this month. Two subcommittees representing competing manufacturers are currently locked in a debate over what to name the signaling metric. One is pushing for "Natural Optical Wavelength Access Yield." The other wants the simplified designator "Wavelength Access Yield." It is expected that the NOWAY / WAY debate will be raging for some time.

Several illustrations of FiFli technology are available through T1 Rex. The first shows scientists investigating the optical emitter characteristics. The second shows a small FiFli swarm communicating within the lab environment. The third is an artist's conception of how FiFli would function as an open standard free of commercialization.