Direct Inward Dialing Saves Lines

Direct Inward Dialing (DID), sometimes known as Direct Inward Dial or Direct Dial Inward (DDI), is a technique for sharing phone lines. Everyone in the office thinks they each have their very own telephone line with their own unique number. You can print this number on business cards, publish it in a company phone directory, and otherwise let the world know it is your private number, just like at home. A thousand people at a thousand desks can enjoy this fantasy without knowing the hidden truth that there are really only 20 or so real telephone lines hooked up.

The sleight of hand involved with DID is based on a special interface between the company's PBX telephone system and the telephone service provider. With DID, the phone company reserves blocks of contiguous phone numbers for you in lots of 10 or 20 and more. What they don't do is hook up copper pairs or digital trunks for all the numbers you choose. Instead, the telco switch detects calls to your block of numbers and connects each incoming call to the next available trunk line to your PBX. You may have only a single DID trunk, a couple of DID analog trunks, or a digital PRI trunk with 23 lines available.

There's one more thing that rides along with the incoming call. It's the phone number or 3 to 4 digit extension number that your PBX system is supposed to ring. That number can be passed to your system through dial pulses, DTMF tones (touchtones), or in the data channel of your T1 PRI trunk. At that point, it is up to your PBX system to ring the correct extension and connect the incoming call.

The person calling doesn't talk to a switchboard operator or encounter an auto-attendant, so they think that they are on a direct line to the person they called. The party receiving the call hears the phone ring and picks up, none the wiser to the fact that they are actually using a shared line. When they hang up, that trunk line will be freed for the next call.

The only way this can go horribly wrong is if you run out of trunk lines due to heavy calling. If your callers can't get through, you can add more analog or digital trunk lines to handle the increased calling volume and maintain the direct phone line illusion.

The companion service to DID is called DOD for Direct Outward Dialing. This is where you dial 9 for an outside line and then dial the number you wish to call. DOD lines are shared just like DID lines. Both analog and digital trunk lines can be ordered as one-way inward, one-way outward or two-way.

Let T1 Rex help you find the lowest prices on PRI and T1 lines with DID and DOD capabilities.



Technorati Tags: pbx

BPL, I Hear You Whistling Through The Wires

When I was in engineering school, we had the best time broadcasting over the power lines. Most campuses of the era had carrier current AM radio stations that legally transmitted their programs without an FCC license to the classroom buildings and dorms. It was all on the up and up thanks to Part-15 of the rules and regulations that permitted sending medium radio frequencies down power lines. The only rule was that they had to stay on the power lines, which limited the coverage area to school grounds.

Now that same idea, transmitting information over power lines, is the center of a major controversy. The technology is called BPL for Broadband over Power Line. It's regulated by the very same FCC Part-15 rules, updated to account for the quirks of sending broadband Internet service over the public power grid.

It's a compelling idea. Not everyone can get broadband via DSL on a telephone line, cable modem service or wireless transmissions. It's expensive to string new fiber optic or copper cables on poles or bury them in the ground. But just look up and you'll see plenty of power lines available.

Electric utility service is about the most universal service you can find. The power lines run underground in cities and subdivisions, then overhead around town and on giant towers as far to the horizon as you can see. If all that existing transmission line can be pressed into service for carrying data as well as power, the broadband infrastructure problem is solved. Even better, every house and office is wired for electrical service. You wouldn't even need to run Cat-5 networking cable. The wires in the wall are your network. No computer, printer or VoIP telephone would need anything more than a power cord to connect it.

As you may suspect, there are some flies in this ointment. The biggest one is that the medium and short wave frequencies used for BPL don't like to confine themselves to the power wiring. They escape by radiating just like radio waves from an antenna. The question is who do they bother and is there a way to avoid it?

The group having the most anxiety over this is the Amateur Radio Operators or Hams. Their hobby involves listening for very weak voice and coded signals from around the world. Even the low power requirements of Part-15 may not be enough to prevent the broadband data signals form BPL from creating static that can drown out faint signals in very sensitive receivers. Actually, any radio service operating in the bands from 1.7 to 80 MHz, including shortwave broadcasts and marine & public service two-way radio, could potentially be affected.

The government has protected certain interests by prohibiting BPL transmission on key channels used by aircraft and excluding operation near coast guard facilities and radio telescopes. Otherwise, BPL is allowed to share channels with commercial and amateur stations, but not to interfere.

The compromise solution to the interference problem is to deal with it on a case by case basis. The expectation is that a relatively few people located close to overhead power lines will actually experience a conflict. When a complaint occurs, the BPL operator will "notch out" or remove a narrow slice of BPL signal on the particular channel being contested. That works because the BPL signal is actually a wide spectrum consisting of hundreds and even thousands of individual carrier signals, each responsible for just a part of the entire bandwidth. Remove a few and you decrease the speed of your BPL service, but not by much. This scheme is called Multi-Carrier Modulation (MCM) or Orthogonal Frequency Division Multiplexing (OFDM) and is widely used in digital signal transmission, including DSL Internet and digital radio broadcasting.

The other fly in the ointment is cost. Power lines were designed to efficiently carry 60 Hz, not 60 Megahertz. Special couplers have to be installed to get the BPL signal around transformers that tend to filter out high frequencies. Repeaters are needed on long stretches of open wire because the low power digital signals fade as they go down the line. At this point, it looks like the population density is too low in rural areas to support the cost of providing broadband over power lines without special public funding.

It's important to remember that the FCC only authorized BPL with updates to its Part-15 rules on October 14, 2004. There have been only a handful of pilot programs with varying degrees of success up to this point. My best guess is that BPL is very unlikely to unseat DSL, Cable and Dedicated Internet services and achieve the dream of the nation's power grid also becoming the nation's data grid. Instead, it will find niches where it works well and is profitable and others where it doesn't. Further technology developments may surprise us the way broadband over telephone lines keeps increasing in speed to where it can now rival fiber optic cables.

In the meantime, we can offer you excellent prices with wide availability for DSL, Cable Modem Internet, and T1 Dedicated Internet service. Get instant price checks and see what's available for your home or business use.

Technorati Tags: broadband

Sharing Phone Lines

Business telephone lines are expensive. You want to have enough of them so that your people can get an outside line at any time, but not so many that they are only used a few minutes a day if at all. You also want to make sure that customers, suppliers and outside personnel can call in without annoying busy signals.

The simplest scenario is a home office or a teleworker operating at home. If usage is very light and you don't need a special business listing, the residential landline or personal cell phone may be enough. If more that one person needs to use the line, you simply add extensions or get a wireless phone system that includes one or more extra phones.

But what if usage is heavy or you want a special line just for that business? One solution is to add a second phone line with its own telephone, answering machine, and FAX machine. Going a step further, install two-line phones so you can select which line you want to answer from anywhere in the house.

This is the start of what's called a key telephone system or key telephone unit. Every phone has all of the telephone lines available. A light next to the line switch tells you whether that line is in use or not. You answer the line that's ringing because its light is blinking, or select a line that is not in use to make your call. If you choose a line that is in use, you have an instant party line conference going.

Many small and even medium sized offices have key telephone systems as an alternative to giving everyone their very own outside line. If your business doesn't require everyone to be on the phone all the time, two, four or six phone lines might be all you really need to service the whole office, factory or store.

The next step up is a PBX or private branch exchange. It's like having your own little phone office. Phones connected to a PBX system do not have phone line buttons. Instead you dial a number such as 9 to get an outside line. The PBX system assigns you next available line when you need it. If you are going to call someone in the same building, you just dial their extension. The call is connected through the PBX and doesn't even use a public phone line.

You can add phone lines to the PBX as your need grows. Once you get up to a dozen or so outside lines, it is often less expensive to consolidate all those individual local lines into a single digital T1 or PRI line. T1 gives you up to 24 phone lines and PRI gives you up to 23 plus caller ID information. If you need more than 23 or 24 lines you just add another interface card to your PBX and install a second T1 or PRI line.

A competing technology is VoIP or Voice Over Internet Protocol. In the home office example, a VoIP phone could be installed instead of a second landline. The VoIP phone or VoIP adaptor connects to the home's router and shares the broadband service with one or more computers. Some VoIP adaptors let you add two phones or one phone and one FAX machine, each with their own phone numbers. If you already have broadband, you'll probably find that using VoIP for a second phone is cheaper than installing a second landline.

With VoIP the concept of a phone "line" gets a bit fuzzy. VoIP converts telephone voice and signaling into data packets that are carried on computer networks or broadband Internet. If you need to add more phones, you increase the capacity of your network instead of adding more wires from the phone company. From an electrical standpoint it seems like one big party line. Unlike the party lines of old, however, every VoIP conversation is separate and private. You don't have to worry about your neighbor picking up the phone and listening in to your conversation ...like many of our parents and grandparents did.

For PBX based phone systems, T1 Rex will help you find the best prices for your T1 or PRI line service.

Copper That Thinks It's Fiber

I was shocked when reading "Om Malik on Broadband" to see an announcement about a new chipset that offers 100 Mbps upload and download speeds on copper telephone wire, of all things. Is this DslMAX, the landline equivalent of WiMAX?

Ikanos Communications, the company that issued the press release on the new chipset, isn't calling its product DSL anything. It goes by the name "FX 100100." The FX stands for fiber extension. At first I thought the 100100 might be a binary 36, but on closer inspection it simply indicates a symmetric 100 Mbps upstream and 100 Mbps downstream data rate.

Fiber extension is the real goal of the Ikanos chipset. The range at this speed is more like a few hundred feet rather than a few miles. The idea is to run fiber optic service to the neighborhood or curb, and then deliver service to the commercial building, apartment building, or single family home using Ma Bell's good old copper pairs. Why such a hybrid arrangement? It avoids the messy and expensive process of trenching fiber for a passive optical network to each and every dwelling. Getting copper to run at fiber speeds has even greater leverage in downtown areas where it can be cost prohibitive or even impossible to go tearing up streets to reach every building.

So how do they do that? I keep hearing that copper pairs are on the verge of being reclaimed by nature after a hundred years in the ground. The only sensible transmission medium for the future is fiber. Right? Well that would be true if we were starting from scratch. Everyone would be installing bundles of glass fibers for data, telephone, television, and everything else. You only need copper to bring in power. In a situation where you are trying to provide new high speed services to an already built-up infrastructure, the lure of using all that in-place copper wiring is just too compelling to ignore.

I'm starting to think that there is something of a "Moore's Law" for copper. Gordon Moore of Intel postulated 40 years ago that processor speed would double every 18 months without knowing exactly what breakthroughs would be needed to keep going at that rate. Yet, it has happened. Copper telephone wire was supposed to be tapped out with 56K dial-up modems. Yet, ISDN and the various flavors of DSL keep pushing the bandwidth limit up and up. Even in the office, copper twisted pair keeps fending off the advance of fiber with speeds up to 1 Gbps and experimentally up to 10 Gbps.

The magic that Ikanos Communications is using is an intelligent set of integrated circuits that combines discrete multitone modulation (DMT), a 150 Mips (millions of instructions per second) microprocessor, plus analog and line driver interfaces. The system is smart enough to measure the characteristics of the particular phone line when it powers-up. Then it cleverly transmits more bits in frequency bands that have less noise, and fewer in bands affected by interference or bridged line taps. The performance comes from the fine tuning required to flow as many bits through that copper straw as you might just dump down a fiber optic fire hose.

For copper based services, T1 Rex can help you get the lowest prices on available business grade DSL and T-carrier services. If you need fiber bandwidth up to Gigabit Ethernet or OC192 capabilities, try our GigaPackets service.

Outsource Your Number Crunching

Computing and data centers are pricey propositions. Small companies can get away with a few PCs and a broadband connection to the Internet. Medium and larger sized corporations are faced with tens of thousands, hundreds of thousands and millions of dollars in capital investment. To that you have to add the recurring costs of electricity, environmental controls, regular system upgrades and the expert personnel to maintain all that magic behind the curtain.

These costs are just the price you pay to be in the modern business game, right? Companies have tried various options to get the same result cheaper, including outsourcing the help desk overseas, using application service providers, leasing equipment and hiring temporary and contract personnel. Now here's a new wrinkle: Outsource your computers.

After years of downsizing human resources, hardware is now the one with a bullseye on its back... er... back of the rack. The selling point is that data centers tend to accumulate rooms full of equipment that starts going stale nearly as fast as a fresh gallon of milk. Just when you think you've got it paid for, it's time to add more machines or upgrade the processors, memory, storage and so on. All the while, these centers are turning electricity into heat and more electricity into air conditioning to get rid of the heat from the computers. This goes on even during times of the day when the loading on the computers is low. Is there any way to offload these costs?

The people promoting grid computing or utility computing think it can be more efficient to treat computing power just like electric power and have it delivered by a utility. You don't find it cost effective to go off the utility grid, so why not consider getting on the computing grid?

Grid computing itself isn't really based on having a single monster computer sitting next to a power plant. It's based on the idea that a super computer can be built cheaper from thousands of small microprocessor based computers, even standard PCs. With the right software orchestrating this army of machines it's possible to get terabytes per second throughput, perhaps even petabytes some day.

Now, who has lots and lots of the latest model computers at their disposal? Why, the computer manufacturers of course. That's why you see Sun promoting the "Sun Grid" for utility computing. HP and IBM have their own offerings. Sun is currently running a promotion offering their 10,000 CPU grid for a buck per cpu-hr. I guess that's $10K an hour if you need all of them. Still, what do you pay for a cpu-hour all told?

Seems unlikely that anyone is going to outsource their office PCs or even a small mainframe. But, if you need massive processing power for a particular project or just in short bursts, utility computing could make a lot more sense than owning. Typical examples include engineering design automation, scientific modeling, financial simulations, and high resolution graphics rendering to make movies.

Sun is actually taking this utility idea further by also offering a storage utility for $1 per gigabyte per month. Now maybe you can give the heave-ho to some of those disk arrays and tape libraries. What WILL you do with all that extra floor space?

If utility computing catches on, we may see a lot more pay-per-use or metered services become available. With high speed bandwidth coming down in price, accessing pooled resources located far away gets easier and less expensive. Perhaps market economics will flip and we'll generate our own electricity with solar panels but buy our computing and data storage from a utility.

Need lots of bandwidth to support your utility computing or other wide area networking needs? Let GigaPackets get you the best competitive offers for optical carrier services.

Connect Aloft With The Flying ISP

Do you suffer from Internet withdrawal when you fly? Does your PC seem almost useless sitting on that plastic tray table? No need to be offline anymore, at least on some popular international routes.

Connexion by Boeing is a broadband Internet service that gives you broadband at 30,000 ft. as you wing your way overseas. You can browse the Internet, send and receive email, and even connect to your corporate VPN. In some cases, it's a flying hotspot. Otherwise, you plug in an Ethernet cable.

So how does Connexion service work? It's satellite based Internet service with the satellite receiver mounted atop the aircraft. That sounds like the satellite Internet service you can get at home, but with one little wrinkle. The plane is moving. Not just moving, but zipping over the ocean at 600 miles an hour. A regular dish antenna wouldn't do any good because it wouldn't stay pointed at the satellite for long.

Instead, Boeing has developed a Ku band phased array antenna that electronically tracks the satellite signal. Phased array antennas have long been used by the military and now weather radar systems. There are no moving parts. The antenna is made up of a number of elements whose signals can be combined to be perfectly in phase in a particular direction.

The Connexion satellite link is a 5 Mbps download and 1 Mbps upload speed to the plane. Like any other ISP or Wi-Fi hotspot, this backbone speed is shared among the users through an onboard router. In many cases, it's a wireless router. You simply set up a wireless profile for Connexion by Boeing and then sign up for service using your web browser. Prices range from $7.95 for 30 minutes use on short flights to $29.95 for full service on flights over 6 hours.

Here's some more good news. Boingo has just announced an arrangement so that Boingo subscribers also have access to Connexion by Boeing. Would you call that Boeingo?

The Connexion service is available extensively on Lufthansa, and also available on Japan Airlines and All Nippon Airways. It should be starting soon if not already available on Scandinavian Airlines.

Check the Connexion by Boeing Website to see if the flights you are interested in have the broadband service available. Service on US domestic flights has been delayed by all the financial problems, but may start as soon as 2006. The FCC is reviewing licensing for the Aeronautical Mobile Satellite Service that could also open the market to other providers.

MPLS Networks Are Coming Your Way

MPLS networking doesn't get quite the same hoopla as IP networking, but it's quietly growing by leaps and bounds. If not already, MPLS may soon be part of your network strategy. Here's the how and why.

MPLS stands for Multi-Protocol Label Switching. The multi-protocol part gives you an idea of how versatile this type of network is. Like IP or Internet Protocol networks, you need a special setup for MPLS. Of course the same is true for SONET, ATM, Frame Relay and other network protocols. MPLS tries to work with all of these other protocols, mostly by encapsulating them in its own tunnels. Why? To add speed and features that you might not otherwise have.

The way this works is that your packets enter the MPLS network through an ingress router that is also known as a tag router. Think of the MPLS network as a sovereign nation and the ingress routers as the customs checkpoints where you enter the country. To get out, you need to pass through an egress router. While you are traversing the network you are routed by tag switches also called label switch routers. It is important to note that your data packets will be the same when they leave the network as when they entered. In between, they will be in the MPLS protocol.

If this sounds a little like VPN tunneling, it actually is. Instead of encrypting the packets, MPLS adds a 32 bit tag to the packet headers. The ingress router examines the desired destination address and creates a tag that chooses a virtual circuit or label switch path for that packet. The ingress router will also assign quality of service requirements to the tag. From that point on, the tag switches look only at the tags to determine how to forward the packet. There may be multiple routes available for each label switch path so that the tag switches can manage outages, congestion and differentiated services. At the egress point, the MPLS tag is removed before sending the packets on their way.

Why go to all this trouble? For one thing, processing the relatively small tags is much faster than having to deal with larger headers at each router. For another, the MPLS network can be designed to provide more bandwidth or shorter latency paths for voice packets in VoIP telephone systems. Video packets really need lots of bandwidth available, so you don't want them crammed into paths where computers are backing up large databases. At the very least, voice and video need priorities to commandeer the bandwidth they need to maintain quality service. Most electronic data interchange isn't quite so sensitive.

Where will you find MPLS networks? Most major carriers now have them or soon will, perhaps as their primary backbone. Network traffic is evolving from time insensitive data transfers to time critical voice streams that are leaving the traditional public telephone network. Experience shows that just piling voice traffic on top of data traffic on wide area networks can lead to poor voice quality and dropped calls. MPLS supports traffic engineering needed to ensure that each type of packet, including voice, video and data, gets the quality of service it needs while on the network.

In fact, MPLS networks are now spreading to include access networks and may eventually find their way into your enterprise network. Service guarantees could be easier to manage when it's MPLS from end to end.

T1 Rex can help you get the MPLS or other network services, including dedicated Internet service, point to point trunking and optical carriers. Let us get you a fast, no obligation quote for the best carrier pricing to meet your specific needs.

Voice Over Whatever

Telephone communication was once limited to heavy desk phones with dials that came in any color you wanted as long as it was black. They were permanently wired to the wall because only authorized telephone company service personnel were going to repair or move them. No way that YOU were ever going to exchange them for something else. There wasn't anything else.

Things have changed, right? Now there's a shooting war in progress between old and new telecom technologies with new and ever more exotic players jumping in all the time. With voice over this and voice over that, how do you know what to pick at all?

Lets take a look at some of the more popular legacy and emerging technologies and what they do:

Analog Phone: Also known as POTS for plain old telephone service. Sounds dull, doesn't it? It may still be your best choice for a single business line or a few lines with a key telephone system or small PBX. The latest wrinkle is bundling local and long distance service for a special price, or even including DSL Internet service in the package.

Voice Over TDM: Also known as digital trunking, T1, PRI, or Integrated T1 service. You don't plug phones into this type of service. It connects through a PBX interface. Your phone works the same whether the line to the phone company is analog or digital. But if you have more than half a dozen phone lines plus company Internet service, you might be able to save on your monthly telecom bill with this option. If you have more than a dozen phone lines and are still using analog, digital service can almost certainly save you money.

Voice Over IP: People like to call this "vOYp". With VoIP your analog phone is replaced by a digital phone and a network connection, same as a computer. That's what it is. Your phone has been taught to speak computer language, in particular IP or Internet Protocol. At the local network level the connection is known as Ethernet. One advantage of VoIP is that computer and telephone networks can be merged into one network since all the equipment speaks the same language. A possible problem is not having a fast enough network to handle both, with the phone conversations usually more affected than the data. Probably the biggest advantage of IP over other network standards is that it is quickly becoming THE network standard. If you want Internet telephony, VoIP is the way to go.

VoFR: Voice over Frame Relay offers a way to make phone calls on a private frame relay network. Many larger companies use frame relay networks to interconnect their various offices and plant sites. Like VoIP, VoFR can be used to share an existing computer network with telephone traffic. Since frame relay networks are private networks, you have more control over call quality than on a public medium like the Internet.

VoATM: No, you don't go to the ATM machine to make a phone call. In this case ATM stands for Asynchronous Transfer Mode. It's a private networking standard something like frame relay. ATM is designed around small cells of uniform size. This design is compatible up to and including optical carrier networks, which offer massive amounts of bandwidth from location to location. Traffic engineering features of ATM networks make quality of service for telephone calls fairly easy to achieve. Many of the well known long distance carriers use ATM as a transmission standard in their own national and international networks.

VoWiFi: Voice over Wi-Fi is a fast emerging technology that lets you make telephone calls at WiFi hotspots. Savvy computer users have been able to do this for a long time using "soft phones" which are software programs running on their laptop computers. If you don't fancy lugging around your computer to make phone calls, you'll soon find cell phones that also work on WiFi or perhaps special WiFi only phones. The technology has a ways to go yet before you can maintain a call as you move from hotspot to hotspot. A more advanced design will let your phone switch seamlessly from cellular to WiFi, depending on which is the best choice for wherever you happen to be.

VoWiMAX: Voice over WiMAX is a more powerful longer range version of VoWiFi that's not ready for prime time yet. When WiMAX becomes generally available in a couple of years, it might just give cellular a run for its money.

Cellular: This is the wireless phone system that is almost universally available for fixed location or mobile use. There are multiple standards worldwide, although you can get world phones that handle just about any cell network. Cell phones that combine voice, PDAs and BlackBerry text transmission are altering our notion of what a telephone really is. When VoWiFi and VoWiMax capabilities are included, it will be possible to integrate the cell phone into the corporate telephone system including PBX features like transfers, forwarding, conferencing, receptionist control and 3 or 4 digit dialing.

Tag: voip

UWB From Titanic to Today

Ultra Wideband, UWB, is touted as a once secret esoteric military technology now being readied to take over the short range wireless market. It could potentially lay waste to Bluetooth, ZigBee and Wi-Fi as it offers the desirable characteristics of very high bandwidth and low power consumption. It could potentially lay waste to all communications if ever allowed to rule the airwaves like it once did, nearly a century ago.

Ultra Wideband is a bizarre transmission system by conventional radio design practice. First of all, there is no carrier wave like you have with AM and FM. That's not unprecedented. SSB or single sideband radio sets are often used for two-way communications on the shortwave bands. The carrier isn't really mandatory. It simply makes for a simple transmitter design and ease of tuning at the receiver. In most communications schemes, the information (audio, video, data, etc.) rides on a carrier wave that is discarded at the receiving end. Instead of a carrier, UWB transmissions consist of a stream of pulses only picoseconds wide. A nanosecond is 1,000 picoseconds if that gives you an idea of how short these pulses are. The pulses themselves aren't ordinary sine waves, they're just impulses.

Short impulses result in high frequencies spread over a wide band. Thus the term ultrawideband. How ultra? A 4 GHz UWB transmission would have a minimum bandwidth of 1 GHz. If you tuned into a UWB transmission, it would sound like white noise on a regular radio. But isn't background noise on transmission channels made up of white noise? Ah-ha. Now you know why the military likes this technology. It's hard to detect without the right equipment. Anyone stumbling across a UWB signal thinks it's just extra noise and won't suspect there is a huge datastream being transmitted.

The invention of UWB tends to be credited to research on microwave transmission in the 1960s. Actually, what happened was that researchers finally had the mathematical theory to understand electrical impulse response plus the test equipment to check their theories. With that they could build a body of knowledge that would lead to practical UWB systems, at least modern UWB systems.

The very first UWB transmissions were made by Heinrich Hertz in 1887 and refined by Guglielmo Marconi into a transatlantic radio system in 1901. And this is where the Titanic comes in. It was Marconi spark transmitters that sent the CQD and SOS emergency signals from the doomed ocean liner in April of 1912.

Marconi had invented a radio system based on UWB simply because an electrical spark naturally generates impulse signals with very wide bandwidth. Any transmission system with a bandwidth greater than 25% of its center frequency can be considered ultrawideband. Radio pioneers considered that a liability rather than an asset. Each transmission hogged the entire low frequency spectrum, preventing other stations from being heard. They quickly adopted the narrowband system using sine wave carriers that allowed many stations to share a band of frequencies.

Today's circuit miniaturization and solid state components make it easy to use microwave bands in the GHz range where there is lots of spectral space available. Or so it seemed. UWB goes back to the idea of spreading out to occupy the whole available bandwidth. But today's wrinkle is sophisticated receivers that can decode complex signals riding just above the noise floor. No one, least of all the FCC, is going to allow UWB to ride roughshod on very expensive communications spectrum. In fact, UWB is now allowed only if it stays below the Part 15 "unlicensed" power levels and even less on frequencies used for GPS (Global Positioning System) transmissions.

Fortunately, UWB is so efficient that less than a milliwatt is all that is needed to transmit hundreds of Mbps as far as 30 feet. That puts it into the category of PAN or personal-area networking, now dominated by Bluetooth and WiFi. True, UWB as currently approved doesn't approach even Wi-Fi hotspot coverage. But who's to say what might be constructed with mesh networks and further advances in the technology?

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Wireless Mesh Networks and Broadband Co-Ops

Instead of getting your Internet service from an Internet service provider, how would you feel about BEING the ISP or at least participating in helping to spread the connection throughout your community? With wireless mesh networks, you're not just a user, you're a provider too. For your participation, you get a share of the cost savings that come from be part of a cooperative effort, or co-op.

The whole model of carriers vs customers is being challenged by a different way of routing packets. Your typical WiFi hotspot has a central 802.11 wireless access point or WiFi base station that acts as the Internet service provider. The various people waiting in the airport lounge or sipping coffee in the cafe are the clients or users of the service. All communications are between the clients and the access point. This client/server relationship is the defacto standard in computing today.

That's today. Tomorrow a different topology may rule. The WiFi card in your laptop might become an access point in addition to its normal role as network client. In mesh networking every node communicates with every other node, not just back and forth to a central router. In another variation, called a partial mesh network, nodes communicate with all nearby nodes, but not distant nodes. This partial mesh network arrangement is what lets you build a community level "hotspot" by passing data packets from node to node until they get to their destination. Each low power access point may only have a range of 300 feet. Two of them push the range to 600 feet, three take you to 900 feet and so on. As computers join the network, they get to send and receive packets from the mesh, but they are obligated to share their bandwidth by also passing along packets that are intended for other users.

It's a very cooperative arrangement. To make this practical, the network needs enough intelligence to understand where nodes are located in respect to others, so that all nodes do not have to route all packets. That would really bog things down quickly. Instead, your node only serves itself and a few others.

So, what force is behind this move to denigrate the traditional ISP? Would you believe it is none other than Microsoft itself? Yes, they are hard at work in Redmond, Cambridge and Silicon Valley on what Microsoft calls "Self-Organizing Neighborhood Wireless Mesh Networks." The IEEE has a working group standardizing the hardware end of wireless mesh networks as 802.11s.

Pushing the Internet Co-Op envelope is the community of Champaign-Urbana, Illinois. They have an up and running project called CUWiN for Champaign-Urbana Community Wireless Network. In this case, the technology consists of specialized access point hardware using outdoor antennas. If you want to participate you need to donate a PC to help with the routing or acquire a Soekris single board computer to mount in a weatherproof enclosure on your roof, along with a 802.11b wireless card and 8 dBi antenna. You can also help supply Internet bandwidth as a network edge node if your provider allows bandwidth sharing. Or you can simply act as a relay node to help extend the reach of the wireless network.

Mesh networks are very robust in that if a node goes down, the rest of the network simply routes around it. As nodes join the network, their resources expand the network and make it more robust. Almost sounds organic, doesn't it?

Will these living, breathing network organisms digest the traditional DSL and Cable ISPs? Not completely. You still need a DSL, Cable, Satellite or T1 dedicated Internet connection to feed the network edge. However, in communities that traditional broadband providers have forgotten, wireless mesh could spawn and preempt any hardwire build-out. Once WiMax nodes become practical, there really is no geographical limit to the spread of mesh networks resembling something of a... web!

Need broadband access to feed your network edge? Get business grade dedicated Internet service from T1 Rex.

Outsourcing The PSTN Gateway

Enterprise VoIP and VoIP based telephone systems for the small and medium business continue to encroach on the turf of the PSTN or public switched telephone network. If you have already implemented VoIP in your organization, you know that your telephone calls piggyback on your data network without any per minute charges, taxes or fees. That is, as long as they stay on your network or the Internet. As soon you need to make a call to someone with a conventional landline or cell phone, or take a call from them, the free ride is over. Now you need to access the PSTN.

How you get to the phone company's network depends on how you've implemented VoIP, but in the background it's all the same. At some point a device called a gateway, gateway router or PSTN gateway converts the packets of your VoIP datastream into analog voice signals of varying electrical current levels. The gateway also handles signaling, which is how you tell the phone company you want to make or take a call and what number you are dialing.

If you have chosen a hosted VoIP service or hosted PBX system, the PSTN gateway is somewhere out there at your service provider. You're typically buying access for so much per month, which also includes routing your VoIP calls.

At the enterprise level, you probably have your own softswitch or gatekeeper, routers, phones and so on for a completely self-contained network. For PSTN access, you have a gateway or hybrid PBX system that you maintain yourself. You also need conventional phone line or digital trunks to the local telephone company office. But what if you could outsource this function and let someone else provide the gateway, similar to the arrangement that hosted plan users have?

Now you can. Broadwing Communications, a tier 1 voice and data networking carrier, is offering a hosted gateway solution called PRIorityConnect SIP. Customers simply route their PSTN bound VoIP traffic to the Broadwing platform using SIP or Session Initiation Protocol. Inbound calls are converted to SIP based VoIP and routed to the corporate network.

That's another vote for SIP as the preferred signaling protocol over H.323, the older and more comprehensive standard. SIP has pretty much become the defacto standard for residential and small & medium business VoIP. It's been making inroads into enterprise VoIP, with many business phones now able to support both standards.

Let T1 Rex get you a quote on competitive voice and data services from Broadwing and other tier 1 providers.

Synchronizing FM Radio Stations With T1 Lines

In the world of radio broadcasting there are large, medium and small stations. The large stations are generally associated with high power and major market coverage. Medium and smaller stations may completely serve smaller communities or partially cover larger metro areas. Big stations mean large audiences and big bucks. But there are only a few available to go around. What would you think of building a huge FM station by combining a bunch of small stations?

The latest digital technology is making it possible to synchronize two or more stations on the same frequency transmitting the same program so that you won't notice when your car radio moves from one station's coverage to another. This is similar to cellular phone service where the radio cells seamlessly hand off your phone call from one to the other, ensuring that you always get the strongest signal possible.

Harris Broadcast Communications has a system called Intraplex SynchroCast that uses GPS receivers and T1 telecom lines to tie stations together so they act like one larger and more powerful transmitter. The system uses Global Positioning System (GPS) receivers at each transmitter to precisely synchronize the carrier and stereo pilot signals. That puts the transmitted signals in phase rather than some random phasing that you would notice when you are situated between stations.

The other important part of this system is using T1 lines to transmit the station audio digitally between studio and transmitters. That's done by stations anyway because digital studio to transmitter links preserve audio quality over a distance of miles. The new wrinkle is to install an additional GPS receiver at the studio and send its timing signals along with the audio to each transmitter.

What this does is let the SynchroCast system determine the time delay of the audio program coming from the studio to each transmitter. Chances are they are different because the transmitters are not the same distance from the studio. SynchroCast adjusts a small digital time delay for each program signal so that they are transmitted from each antenna at exactly the same time. The programming will then arrive at the point between stations correctly in phase so you won't be able to tell when your radio switches from station A to station B.

Clever, right? With an arrangement like this, a broadcast company can buy up smaller stations on the same frequency that ring a metro area or are located along an interstate highway. Listeners will be able to hear the programming much further than if they had to switch stations to find the same program. They'll also avoid the distortion that you get when stations on the same channel carry the same program but are not synchronized.

If you are in the radio, television or audio network field and are interested in T1 lines for audio transport, let T1 Rex help you get the T1 links you need at the best prices.

The Shock and Awe of Competitive Quotes

The standard procedure for getting digital business lines such as T1 or T3 service has been to call the local phone company and place an order. A sales representative in a suit might stop by with the contract and show you where to sign, but the price is what the price is. Well, that's how it USED to be anyhow.

Since telecommunications deregulation, competitive suppliers have sprung up with their own networks and pricing that can be much lower for standard T1 line service or fractional T1, integrated T1, bonded multiple T1 lines, DS3 service, a T3 line or even optical carrier service for OC3 and higher speeds.

If you have been signing the standard telco contract over and over, your eyes might just bug out when you see what else is available that you didn't even know about. In fact, the telecom business has become so competitive since the end of the "boom" years of the 1990's that you can almost certainly save money on any contract more than a year or two old. Perhaps even the contract you just signed a couple of months ago.

So how do you find these great deals? You have to know somebody. Us. Actually, you could search around and find a few competitive providers and go through the bid process with each. Or, you can use a telecom brokerage service like the one we have available. Brokers negotiate the best rates possible from as many top tier suppliers as they can. Ours has a dozen. Plus, we have access to something you can't do on your own and that is get automated quotes while you wait.

Dedicated services are priced based on distance to the nearest POP or point of presence for the service provider. The tool we have available lets you enter your business phone number and street address and get a list of available options in a matter of seconds. The database is programmed for automatic T1 and T3 line service quotes. Optical carrier services are more complex and one of our consultants will call you with a quote.

So, are you sitting down and NOT holding a cup of coffee? Well, put it down before you run any quotes or you might just dump it all over your keyboard... and we don't want that to happen. Now, click here to get your complimentary dedicated line service quote.

Control Your Computers With KVM

KVM is a technology that lets you control 2, 4, 100 or 1,000 PCs or servers from a single keyboard, monitor and mouse. Take command of that virtual data center from the comfort of your office or simply switch between a couple of different local computers while you're doing Web design or programming. There's a level of KVM that's just right for you.

First of all, let's explain those initials KVM. They stand for Keyboard, Video and Mouse. Those are the three peripherals every computer needs to make an operations console.

The simplest arrangement is a KVM switch which is a device about the size of a modem. You plug your keyboard, monitor video and mouse into the KVM switch instead of a computer. Then you run a set of KVM cables from the switch to each computer you want to control. A 2 port KVM switch controls 2 computers. You can also get 4 port and 8 port KVM switches in a desktop size.

How do you work KVM? You can push a button on the KVM switch to move from computer to computer. Or, there are keyboard shortcuts you can use to make the switch back and forth. Another mode automatically switches the monitor between computers every few seconds so you can keep an eye on what's going on. That's especially useful for monitoring a group of servers that you expect to run automatically. If you need to intervene to fix a problem or install new software, simply select that particular server on your KVM switch.

This simple type of KVM switch will work up to about 50 feet away from the computers you are controlling, so it is generally used in a server room or office environment. If you want to get farther away, you'll need to install a Cat5 KVM switch or a Cat5 KVM extender. These use Cat5 computer wiring instead of the short bundles of keyboard, video coax and mouse wires. With a Cat5 KVM switch you can move your control point hundreds of feet from the server room. Some of these switches are stackable so that you can add KVM switches to control dozens or hundreds of machines from one console. A matrix KVM switch lets you have multiple consoles to let several operators have access to any desired server or PC.

KVM switches and Cat5 KVM switches are analog devices. The signals are analog control signals that use their own wiring network between devices. This is also called out-of-band KVM control. In-band systems work over the company LAN, much like the way VoIP telephones and computers share a common LAN network.

Digital KVM uses IP transmission for in-band operation. These are the newest and most sophisticated KVM switches. With IP networking built-in, there is no distance limitation. You can sit in your office in Chicago and control a data center in Asia if you wish. Or set up a "virtual data center" with servers in scattered locations. It's all the same when you are accessing them over the Internet.

That brings up a good point about security. Remote KVM solutions need security features such as encrypted transmissions. This is typically built into the system, essentially creating a virtual private network specific to your KVM over IP system.

Small KVM switches like those made by Belkin can be purchased at office supply stores for control of 2 to 4 computers. Larger Cat5 KVM switches and digital KVM systems are sold by companies such as Raritan, Avocent, and Rose.

IP bandwidth including virtual private networking is available through T1 Rex.

Dedicated Internet for Farms

Agribusiness is now high tech business. GPS systems in tractors keep tabs on exactly how much acreage has been planted and harvested. Livestock is electronically tagged and monitored to know the health of each animal and the costs involved in raising it. Everything from buying seed to monitoring market prices to keeping tabs on the weather is computerized. Yet, getting high speed voice and data connections in rural areas can still be a challenge.

A large part of the problem is that the methods of Internet access most popular for small business and home businesses are based on technologies with limited delivery range. DSL, including low cost consumer ADSL and business grade SDSL, can't be delivered more than a few miles from the nearest telephone company central office. In fact, the speed of a DSL connection goes down rapidly as you get farther from the DSLAM (digital subscriber line access multiplexer) that feeds the broadband Internet signal down the phone line.

Cable Modem Internet service is also limited. Cable companies may run their lines to a few outlying subdivisions and then stop. Their business model is based on dense populations so that they can get a lot of TV and Internet subscribers for every mile of expensive cable buried or strung on poles.

WISPS or Wireless Internet Service Providers are sometimes an option, but they are also limited in range and need a line of sight path from their tower to the antenna they set up on your property. When WiMAX enters service starting later this year and next year, coverage will greatly expand and wireless Internet service to farms, ranches, vineyards and rural residents will become more available.

That really leaves only two good options right now for Internet service on the farm. A very practical and professional grade Internet connection can be provided using T1 line service. T1 is a technology developed by the telephone companies for long haul of telephone and data traffic. As such, T1 is available just about anywhere you can get a telephone line. In fact, T1 is transported on two pair of ordinary copper phone wires with special regenerators spaced every mile or so to maintain signal quality.

That's a big difference between T1 and DSL. T1 was designed with means to keep boosting the signal out to 20 miles or more from the telco office. With T1 you get 1.5 Mbps both upload and download with a service level guarantee to ensure reliable operation. With T1 you have the speed to run multiple computers, VoIP telephone or a hosted PBX system, and even a web server if you wish. If you don't need the power of a full T1 connection, fractional T1 service is available for a lower price. In some areas, Integrated T1 lets you share the line for Internet access plus a small PBX or key telephone system for your business phone calls.

If you are interested in T1, Fractional T1 or Integrated T1 service to your farm, ranch, vineyard or rural homestead, let T1 Rex find the best T1 prices for you.

When Dial-Up Internet Service Makes Sense

In the great migration to residential broadband and T1 dedicated Internet access for business, it's easy to forget that nearly half the people accessing the Internet in the US are using dial-up modems on standard telephone lines. Dial-up access has improved greatly over the years and still makes sense for many people, even business people.

But isn't dial-up Internet so last century? Not necessarily. For instance, how can you get your email or visit web sites when you broadband goes down? That happens even to the best DSL and Cable Internet providers on occasion. It helps to remember that much of the time broadband is a convenience more than an absolute necessity. In a pinch, you can live with plugging a phone wire into the back of your desktop or laptop and dialing into 56K Internet service.

Not everyone lives on the Internet like some of us. There is no point in paying $35 to $45 a month for broadband or $24 a month for the heavily advertised dial-up services if you only log on an hour a day to check your mail and a few web sites. If you are online 15 hours a month or less, consider CogniSurf for $7.95 a month. Or, for unlimited dial-up access you can go with WorldVerge at just $9.95 a month.

What do you get for your $9.95 a month? WorldVerge offers unlimited 56K dial-up Internet service with spam and virus filtering, 5 email accounts, free 24/7 tech support and both standard PC and Macintosh dialers. Add the accelerator option for another $2.95 a month and you'll be downloading email and accessing web sites up to 6 times faster. That's almost the broadband experience, although accelerators don't affect the speed of software downloads & web site FTPs, and don't improve VoIP pc to phone calls over dial-up.

Dial-up Internet service is alive and well and less expensive than ever for broadband backup, business travelers, occasional users, and anyone living in areas that aren't supported by DSL or Cable Internet service.

Your Next ISP is a Blimp

One thing about rural cellular phone service and all wireless broadband transmission is that the towers just never seem to be high enough to get the coverage you'd like. Why? Towers are expensive. The higher you go, the more expensive it gets. Just ask any television station owner. But think of the wireless coverage you could get with, say, a 65,000 foot antenna.

That 12 mile high antenna may be coming to your city soon thanks to a company called Sanswire Networks, a subsidiary of GlobeTel Communications Corp. No, this isn't one of those crazy ideas about tethering towers in space. Well, not yet anyway. What Sanswire's doing is re-inventing the airship. Oh, the humanity! Will we witness a re-enactment of the Hindenburg? Look out, Lakehurst!

Seriously, the Sanswire "Stratellite" is more like a cross between the Goodyear Blimp and the Solar Challenger, a solar powered ultra lightweight aircraft. One difference is that it is unmanned. The Stratellite will be filled with helium for lift, solar cells for power, and electric motors for mobility. It will climb to an altitude of 55,000 to 65,000 feet and hover there for a year and a half at a time. This altitude is above the air lanes and nearly all weather and is called the stratosphere. Hence, the idea for the name Stratellite. It's a cross between stratosphere and satellite.

So why not use a real satellite in space instead of a blimp with a radio transmitter? Cost is one big reason. A Stratellite will cost half the price of an Earth orbiting satellite or less. Plus, when it needs servicing, it will be commanded to land for refurbishing while another Stratellite takes its place. Orbiting satellites turn into meteors and burn up in the atmosphere when they need to decommissioned.

Another big consideration is latency. At 65,000 feet, there is very little latency or time delay due to the speed of radio wave transmission, which is 186,000 miles per second. Low Earth orbiting satellites also work well for telephone service, but you need a lot of them since they zip past any given location in a matter of minutes. Geosynchronous satellites, the ones that stay put, are 22,241 miles out there. That's a time delay of around 120 milliseconds for a signal to get there and just as long to come back, or a bare minimum of 240 milliseconds latency without considering any equipment. This is why satellite Internet services haven't worked well for VoIP phone. The latency is just too long. Each party has to wait to talk, like with a walkie-talkie.

A Stratellite, however, would be perfect as a virtual cell tower, paging service, WiMax transmitter, or the world's greatest WiFi hotspot. Just one could cover an area about the size of Texas. They can be parked in place using GPS receivers to know and hold their position.

How soon before we start enjoying Internet via blimp? The first Stratellites are expected to go into service this year, perhaps within the next few months. If the technology proves to be as promising as it seems, Stratellites could be hovering over all the world's major cities soon. Wait a second. Isn't that how the movie Independence Day opened?

Why TDM Voice is Hard to Beat

In the world of telephone technology, TDM or time division multiplexing is the gold standard. It's the technology currently used for most long distance phone calls and any calls that go between different telephone company offices. Yet, TDM seems to be on the way out. Why? Let's see.

A standard phone line from your home, office or PBX system to the telephone company is an analog line. It's the same varying current signal that was invented by Alexander Graham Bell. You can have one phone or modem call per pair of telephone wires with this scheme. The phone companies originally used a scheme called FDM or frequency division multiplexing to stack multiple calls on phone line trunks or microwave relay stations. Unless everything works perfectly, these calls can interfere with each other or "crosstalk." Years ago you could often hear strange noises and even other calls in the background when you made a long distance call.

TDM solved that. The TDM or digital trunk system digitizes each phone call and gives it a private channel on a T1 or larger digital trunk line. A T1 line has 24 channels available. A larger T3 line has 672 channels. Now here's why it works so well. The digitizing process uses what is called a waveform coder that creates an exact representation of the analog phone signal in a digital format. It stays in that format so that it isn't subject to noise and distortion until it is reconverted back to analog at the far end by a waveform decoder. All along the way, the call has its own channel all to itself. Nothing interferes with it.

This carefully controlled process, which gave us crystal clear phone conversations on undersea fiber optic cables, has the seeds of its own downfall. The problem is that when you are not using all channels available, they are still being transmitted from point to point empty. Like empty boxcars on a train. There are other coding schemes that reduce bandwidth by anywhere from half to ninety percent, but the TDM channels are a fixed size and can't take advantage of newer developments.

The main competitor to TDM is VoIP. VoIP calls are transmitted as a series of packets that are sent through the network but they don't have their own channels assigned. Instead, all packets go down the same pipe. If they are sent over the Internet they may take differing routes to the same destination. VoIP calls are digitized like TDM, but can select from a variety of coders and decoders (codecs) to trade off voice quality for bandwidth savings.

VoIP can share the same network lines as computers rather than needing a specialized telephone network. That's a big potential cost savings. Another savings comes from being able to use bandwidth for data anytime it isn't needed for voice. That makes for better utilization of resources.

VoIP's challenge is to maintain voice quality while enjoying a cost savings over TDM. To do that, some of the TDM quality control measures need to be added to the VoIP system. For instance, you can select the same codec for VoIP that is used for TDM, or at least one that sounds as good to the callers. There needs to be enough bandwidth at all times for voice and data or voice quality will suffer. If bandwidth is limited, routers need to give priority to telephone calls over data transfers during periods of congestion. Private IP networks are more controllable than the Internet, although there are big advantages to be gained by using the almost universally available broadband Internet connections. This is especially true for teleworkers, mobile workers and virtual offices.

Wireline TDM is still an excellent choice for business telephone use, especially for traditional key telephone units and PBX systems that were designed for this technology. VoIP and various wireless standards are coming on strong, though, and have the opportunity to perform as well as TDM service with potential cost savings and additional features that come with new technology.

Get the latest reduced prices on TDM voice and data service or transmission bandwidth for VoIP.

Enabling Telecommuters

As the computer becomes the primary tool of the workplace, more and more jobs become candidates for telecommuting. Telecommuters are employees of companies who only occasionally, if ever, set foot on company property. Instead of commuting by car, they telecommute by telephone and broadband links.

Software programmers, technical writers, sales reps and forms processors are the first category of employees and freelancers who come to mind with the idea of telework. But VoIP and virtual private networks now make it possible to enable a much larger group of tasks to be done off-site. How about switchboard operators? Yes. Accounting, purchasing, computer help desk support, publishing, design and support engineering, sales and marketing, and just about any type of data entry or report generation are candidate tasks. If someone uses a computer and/or telephone in their work rather than physically operating machinery or moving things around in the factory, they might do just as good a job from a nearby remote office or at home.

The basics tools of telecommuting are the computer and the telephone. For a sales representative calling on customers, that's probably a laptop and a cell phone. For a home office, a cable modem or DSL Internet broadband connection makes the most sense. If you are dealing with sensitive company data, you can protect it during transmission by encrypting your Internet connections with VPN software.

A regular telephone line with a speakerphone or an inexpensive headset will do for a telecommuter's basic voice communications. For not much additional money, you can integrate them with the office team by using a hosted PBX system. The home worker gets a business style VoIP telephone that plugs into the router that serves their PC from the broadband connection. Now they can join conferences, accept transferred calls and dial team members using only 3 digits. It's a company phone, so the company gets the phone records and a smaller-than-you-might-think monthly bill.

One step up is the VoIP Videophone. The new ones put many corporate videoconferencing systems to shame. You get color full motion video at both ends over a broadband connection, plus the ability to feed videos or presentation slides down the line.

For employees on the road, billable calling cards offer low rates and good record keeping. There are services that let you send faxes and receive faxes via email. Prepaid dial-up Internet gives you worldwide Internet access via toll free numbers for situations when broadband is not available.

When you think about it, outsourcing is little more than a grandiose version of telecommuting. Companies that are flexible enough to enable telecommuting have the advantage of a nearby labor pool that doesn't need much in the way of company facilities. They may also be highly motivated by the opportunity to better integrate their personal and professional lives.

Wavelength Services for Bandwidth Ala Carte

When we think of fiber optic carrier services, it's generally in terms of lines and channels. Wavelength division multiplexing has now added the option of leasing a lambda. A lambda is one of many individual wavelengths or "colors" being beamed down a fiber optic cable. It's like having a whole fiber optic circuit to yourself, but for a LOT less investment than trenching your own fiber network.

WDM or wavelength division multiplexing turns a single laser beam in a fiber optic cable into many beams sharing the same cable. The beams don't interfere because they are at different wavelengths, like colors of the spectrum. Each wavelength corresponds to a different carrier frequency in wireless lingo.

There are two flavors of WDM. CWDM or coarse wavelength division multiplexing is less demanding technically and provides 16 or so lambdas per cable. DWDM or dense wavelength division multiplexing is more technically challenging and spaces the individual wavelengths closer together. This gives typically 64 different lambdas and up to 80 or 100 lambdas, depending on the optical multiplexing equipment available.

Now, here's what makes WDM exciting. Fiber optic carrier services like OC3, OC12, OC48 and OC192 are based on SONET Synchronous Optical NETwork standards. SONET provides channels within a TDM based transmission scheme. Whatever you want to transmit first has to be formatted and loaded into available SONET channels, usually in ATM cells. At the other end, your data is recovered and restored to its original format. There is cost and inefficiency built into this process, including latency and jitter. Plus, when the line capacity is reached, you're out of channels and out of luck.

Lambdas are different. Buy a lambda and you can send whatever you want down that wavelength regardless of what other customers are doing with their lambdas. Some wavelengths might be used for OC48 SONET. Others can directly transmit Gig-E Ethernet signals or ATM, Frame Relay, Fibre Channel, or ESCON. This is known as protocol independence. Use a different protocol running natively on each lambda, and you don't have to worry about how to make them work together. One lambda doesn't even know the others exist.

If you would like to explore managed wavelength services or traditional SONET fiber optic carrier service, our consultants will be happy to quote prices and availability for your locations. No cost or obligation for this service through GigaPackets.com.

What's The Difference Between T3, DS3 and OC3?

One thing about the telecommunications industry is that there is no shortage of acronyms. How about T3, DS3 and OC3? Or T1, DS1, DS0 and DSL? You can tell these players, but you'll need the scorecard and here it is.

In a practical sense T3 and DS3 are used interchangeably and mean the same type of service. T3 means trunk line, level 3 and DS3 means digital signal, level 3. They both refer to a 45 Mbps time division multiplexed synchronous digital voice or data service.

If you want to get picky, DS3 refers to the digital signal service which could be provided on a T3 coaxial cable or a fiber optic cable. T3 is part of the T-carrier system and refers to the physical line, which is copper wire. You can get DS3 without the specific T3 wires, but not the other way around.

T1 is the other popular T-carrier service. It is a 1.5 Mbps line traditionally provisioned on two pair of copper phone wires. Some providers are now using a single pair to transmit T1 using a more advance modulation scheme than was originally specified. At any rate, the digital signal level for T1 is called DS1.

What is DS0? That's the lowest DS rate specified, which is 64 Kbps or just the right size to carry one telephone call or one dial-up modem connection. DS1 is made up by combining 24 DS0 channels. DS3 is made up of 28 DS1 channels or 672 DS0 channels.

DSL is something else entirely. It stands for Digital Subscriber Line and is a completely different format, although it typically runs at speeds similar to T1 lines. Go figure.

Now where does OC3 fit into all of this. Actually OC3 is part of the optical carrier numbering scheme called SONET for Synchronous Optical NETwork. OC3 runs at 156 Mbps. So OC3 has nothing to do with T3, or does it?

You see, the common theme that runs through all of these digital transmission schemes is the basic design of synchronous time division multiplexing based on the DS0 channel. Why? Because DS0 carries exactly 1 telephone call and that's the lowest common denominator for the telephone companies who designed the standards. Would you be surprised to learn that one OC3 can carry 3 DS3, 84 DS1, or 2,016 DS0 channels?

The T1 or T3 service you order might be delivered on a dedicated copper wire circuit or it might be dropped off from a larger OC3 fiber optic cable. It depends on which hookup is most economical.

Confused? Just remember T3 and DS3 refer to the same thing. OC3 is much faster, and more expensive.

Whatever digital service level you need, T1 Rex can find you the best rates from multiple competing carriers. Get instant quotes for T3 and DS3 service. Or, request a quote for OC3 or higher fiber optic carrier service through our special GigaPackets service.

Why PRI Over T1?

PRI or Primary Rate Interface is a digital telephone service that is popular with call centers, PBX telephone systems and dial-up Internet Service Providers. It is one of the ISDN or Integrated Services Digital Network standards. So, why PRI?

PRI is also called T1 PRI because in the USA, Canada and Japan it is provisioned on a T1 carrier trunk. But, wait. Isn't there also a service called T1? Yes, indeed. PRI might be considered just another flavor of T1 line service. Here's how they work.

The classic T1 transmission format carries 24 digitized telephone conversations. That's called channelized T1. You get 24 channels of 8 bits each per T1 line. But, you also need signaling for each phone call. To accomplish this, one bit from each channel is "robbed" for this purpose, leaving 7 for the actual call. That's called robbed bit signaling, in-band signaling or channel associated signaling.

Another way to format the T1 line is use the PRI scheme. In this case, you get 23 channels per line for phone or modem calls with the 24th being used for signaling to support the other 23. With PRI, each voice or "bearer" channel keeps all 8 bits for the digitized call. This separate data channel, called out of band signaling or clear channel signaling, has a lot more capability than the robbed bit scheme. With PRI you can get Caller ID or ANI automatic number identification. The out of band signaling arrangement also results in faster call setups and tear downs, which is important to call centers and ISPs. PRI channels can be configured as inbound only, outbound only or two-way.

So, how do you choose between channelized T1 and PRI? It depends on your application and the capability of your equipment. If having caller information is important for computer telephone integration (CTI), ISP billing, or displaying caller ID on desk phones, you'll want PRI service. If those aren't important features and you'd prefer to have all 24 channels available for phone calls, or if you have a PBX system that doesn't support PRI, then channelized T1 service may be your better choice.

Creating The Virtual Office

It's the common blueprint for entrepreneurial success. A few friends come up with a new idea that is going to take the world by storm or at least make them millionaires while they are young enough to enjoy it. They sketch out their plans on napkins at a local watering hole. Then they invite a few more key players to join their venture. Before you know it, a building is rented and the new company logo is being affixed to the entrance.

This is the dream that helped make possible the tech boom of the 90's. Today, venture capital is a bit harder to come by and the people you need to launch your dream may live nowhere nearby. But today you have more options. You can build a business without an edifice. You can build a team with everyone right where they are. It's done with the virtual office.

The virtual office that I'm referring to is based on a hosted PBX system. Instead of regular phone service from local providers at each location, business team members each have broadband connections that they use for both Internet access and telephone services. Phone services are provided using VoIP technology, but not just any VoIP service. The key is having a unified system that makes everyone feel like they are part of the same organization. In a bricks and mortar situation, it's often the PBX system that ties all of the desks and offices together. In a virtual office, a hosted PBX system does the same thing.

What's a hosted PBX? It is a service that provides PBX type features without you having to own and maintain a physical PBX or IP PBX. Think of the host like a web site host. The beauty of the Internet is that it's just as easy to communicate with someone half-way around the world as it is to communicate with someone on the next floor of your building. The PBX host can be located anywhere. Workers in the virtual office can be located anywhere.

Anywhere really can mean just about anywhere. Your business partners can be working out of storefronts, loft spaces or home offices in various cities and states. Some can be located overseas. The one common denominator you all require is broadband access.

So how does the hosted PBX simulate an office environment? You dial each other with 3 digit extensions, just like in the office. You can set up an auto attendant with a main number for the company so your suppliers and customers can dial you by extension or name. You can easily park, forward, transfer or set up a three-way conference for any phone conversation. You can even designate one person to be the operator or receptionist using switchboard software that runs on a PC. That operator, by the way, can be... you guessed it... ANYWHERE!

The Holy Grail of Five Nines Reliability

Five nines reliability. It's the standard often quoted for traditional telephone service, a goal for new competitors, and a bragging point for equipment vendors. But what does it really mean? Just how close to perfect is five nines anyway?

The spoken term five-nines refers to the number 99.999%. Count the nines. This number is generally referred to as a reliability figure. Actually, what people call reliability is more correctly called "availability." It's not just how often a piece of equipment has a software crash or a power supply that bursts into flames that is really important. It's how much of the time you actually get to use it. In other words, how much of the time is this particular device available. Availability includes how often it breaks and then how fast it gets put back into service. You also have to include how often it is out of service or unavailable due to routine maintenance.

Here's an example. Say your softswitch has a software glitch that only shows up under obscure combinations of events. When the glitch occurs once every six months, the software crashes and automatically reboots. That takes a minute. Does this switch have five nines uptime? Yes. Now if a power supply smokes once a year and it takes 20 minutes to fix it, that's not good enough for five nines even though the power supply failure occurs less frequently.

Here are some handy numbers to give you perspective on the whole nines issue:

Five nines or 99.999% availability means 5 minutes, 15 seconds or less of downtime in a year.

Or, if you are really ambitious, shoot for six nines or 99.9999% availability, which allows 32 seconds or less downtime per year.

Otherwise, four nines or 99.99% availability allows 52 minutes, 36 seconds downtime per year.

Three nines or 99.9% availability allows 8 hours, 46 minutes downtime per year.

Two nines or 99% availability allows 3 days, 15 hours and 40 minutes downtime per year.

One nine or 9% availability allows over 332 days of downtime per year. That's right. You're only up and running about a month out of the year on average. Good grief.

Zero nines is totally, absolutely useless. It's 100% downtime per year. Perhaps you can get a little something for it from the recycler.

How do you get more nines? Buy the best equipment that's the easiest to repair. Then add redundancy. Highly reliable systems often include multiple power supplies and processors, battery backup, diesel or natural gas generators for longer power outages than batteries can handle, multiple diverse communication lines and extras of whatever else is likely to fail. Buggy software that crashes all the time is going to hurt your reliability. If it goes down a lot and takes a long time to get back online your availability will be hurt also.

One thing to be aware of is the five nines criteria tends to apply to whatever the person quoting it says it applies to. PBX systems that meet five nines availability may only do so for the core system and might not include individual line cards and certainly not the phones themselves and their wiring. If it's REALLY important that you minimize downtime, you need to consider EVERYTHING that can fail and make sure it is backed up and/or very easy to fix.

Let T1 Rex help you find the best prices on bandwidth with the service level agreements you require.

Does Your VoIP Have a Lifeline?

The whole idea behind VoIP is to avoid the PSTN or Public Switched Telephone Network as much as possible. The PSTN is like a toll road. Every time you use it you have to pay a toll. The Internet is more like a freeway as far as telephony goes. Once you pay for access there is no nickel and diming for each phone conversation. But, what happens when your VoIP network slows down like a congested highway or some accident stops traffic altogether. Now what do you do?

The easy answer is to get back on that PSTN tollway until your VoIP is available again. That option is now being included in some of the newer ATAs, Analog Telephone Adaptors, used for single and dual line VoIP or hosted PBX solutions. The extra port is called a "PSTN Lifeline" or sometimes an FXO Interface. FXO stands for Foreign Exchange Office, which is a connection to a normal phone company line.

With ATAs that include a PSTN Lifeline, you plug your phone and broadband connection into the adaptor and connect the lifeline port to a regular analog phone line. It's a standard RJ11 telephone jack like you'd find on the back of a telephone. The magic is that when your VoIP service is down because of a broadband failure or a problem with your VoIP provider's proxy server or softswitch, the ATA will automatically switch your calls through to the public telephone network locally. Some ATAs automatically route 911 emergency calls through the PSTN lifeline, since not all VoIP services offer E911 service.

Examples of VoIP Analog Telephone Adaptors that include a PSTN Lifeline or the ZyXEL Prestige 2002L and the Grandstream HandyTone 486. It's likely that you'll be seeing this feature on more ATA products in the future.

At the Enterprise level, FXO ports are commonly included in routers being used for VoIP traffic. They are used as lifelines but also to give phones in one area the ability to make "local" phone calls in another. The calls travel from office to office over the corporate WAN and then are terminated to an FXO port at the destination location. This avoids paying toll charges when you have a perfectly good T1 or other high speed digital line running between locations already.

You can read more about how ATAs work in my article "Turning Analog Phones Into VoIP Phones." You might also be interested in reading "Hosted PBX Lets Small Businesses Act Big." Visit Enterprise VoIP for more VoIP information and solutions.



Tag: voip

Way Beyond 3-Way Calling

Simple conference calls are easy to set up when you have 3 way calling on your home or office phone service. But what do you do when you have dozens or hundreds of people who want to participate?

For discussions between groups at 2 or 3 locations, you can corral people in conference rooms and let everyone take turns on speakerphones. That works well on particular projects when teams are co-located at each end.

Now, how about connecting a dozen people in a dozen different locations? How about including 500 shareholders in an investor relations meeting? How about just connecting family members scattered around the country at Thanksgiving? For that, you need hosted conference calling.

Simple systems like CogniConference let you set up your conference calls with a web based interface. You invite those you want as participants by giving them a toll free number to call and a PIN number or password. That keeps out interlopers. Each location is called a "leg" whether it has one person on a regular handset or a group gathered around a speakerphone. You can have up to 16 legs on a conference call. Some of them can even be located overseas. You pay a small per minute fee for each leg for the amount of time they are connected.

A more sophisticated system such as Ultra Conference can handle a few or hundreds of participants. You can run the conference yourself or choose to have an operator attend to host the call or even call out to participants. Other features include the ability to record your conference calls to play back later, perhaps on the company web site. The moderator can choose to go into "lecture" mode to eliminate background noise from all the participating callers. This is perfect for sales training sessions where you have one or two people presenting and dozens or hundreds listening. Later in the call, the moderator can return to "conference" mode for a question and answer session.

Ultra Conference offers a couple of different payment plans. With the flat rate plan you pay so much per month to have as many calls as you want. Callers dial a regular phone number and pay for the call themselves. The per minute plan includes a toll free number like the CogniConference service. As host, you pay for the calls.