What Does “Five Nines” Mean to You?

By: John Shepler

Five nines reliability. It's the standard often quoted for traditional telephone service and top network equipment vendors. But what does it really mean? Just how close to perfect is five nines anyway? Let’s take a look.


Reliability or Availability
The spoken term five-nines refers to the number 99.999%. 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 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.

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.

By the Numbers
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. This is often acceptable for many non-critical applications.

Two nines or 99% availability allows 3 days, 15 hours and 40 minutes downtime per year. That’s somewhat marginal for business.

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.

Zero nines, of course, is totally useless. It's 100% downtime per year.

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 & processors, plus 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 also be hurt.

Include Everything
One thing to be aware of is that 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.

On Cloud 9’s
Another option to consider seriously is to move all those hardware availability issues to the cloud. Cloud services aren’t perfect, either, but they often can provide higher service availability than you can afford locally. That’s because the cloud architecture is designed for considerable redundancy and fast failover when problems occur. If you do opt for the cloud, though, be sure you have highly reliable bandwidth connections to your provider. A 5 nines hosted PBX system isn’t all that available if you have a flakey internet connection from your facility to the cloud. A dedicated SIP Trunk or a set of redundant trunks is a much better solution.

Nines for Your Needs
How many nines do you need and what’s the cost for WAN or cloud availability? Get the best price vs performance options for your particular requirements now.

Telephone Trunks for Call Centers

By: John Shepler

All businesses need telephone lines of some sort. Independent professionals may rely on a smartphone for wireless communication, but businesses with offices or stores open to the public or with two or more employees almost always have some sort of landline installed. Let’s take a look at the analog and digital options available and the advantage of installing telephone trunk lines to increase capacity and reduce cost.


Plain Old Analog
Analog phone lines are the legacy technology of the phone companies going back over a century. You’ll hear them described as POTS or Plain Old Telephone Service. POTS lines are well established, highly reliable and engineered for high voice quality on both local and toll calls. Standard phones, including desk sets and cordless phones with multiple handsets, are analog phones and plug directly into analog business phone lines.

Broadband Phone
The digital solution for a single phone line is a broadband Internet connection shared with the computers. This option is usually chosen for its low cost, but voice quality can degrade and certain applications, like FAX machines and alarm systems, may not function correctly.

Adding More Lines
What about the vast majority of businesses with more than one phone line, especially those with an in-house contact center or specializing as a call center? Small operations sill rely on analog phone lines. You can add analog lines one at a time and plug them into your key telephone system or PBX switching system. Each outside line has its own phone number.

How Costs Add Up
Adding analog phone lines incrementally as you need them works well until you get more than half a dozen to a dozen separate lines. There are no technical issues, but costs mount up. Two lines cost twice as much as one line. Six lines cost six times as much. There is no economy of scale as these are independent lines.

How Trunking Saves
The strategy for reducing costs while maintaining voice quality and reliability is called trunking. Trunking simply means combining multiple lines to create a single trunk line with the same capacity. Trunking was invented by the telephone industry to transport dozens or even thousands of phone conversations efficiently from switching office to switching office. Originally, this was done with analog technology called carrier telephony. In recent decades, it’s all gone digital from office to office, leaving analog POTS lines only for that last mile connection between the telco office and the customer’s premises.

T1 Telephone Trunks
The first digital trunk line that was introduced by the phone industry for business users was the T1 telephone line. Yes, this is the same T1 technology that you may be using for point to point or dedicated Internet access. The difference is that the T1 line is divided or “channelized” into 24 separate segments or time slots. Each channel can transport one two-way telephone conversation and is the equivalent of an analog POTS line. You can use an appliance called a channel bank to convert between analog phone and the T1 line. Most in-house PBX phone systems have the necessary interface to do this or it can be added easily with a plug-in card.

Cost Advantage of T1
The big advantage of T1 trunks is that they become cost competitive with multiple POTS lines when you get over 6 to 10 outside lines. If you need more than a dozen phone lines for your desks or a call center operation, T1 is the lower cost option. Multiple T1 lines can be added to provide blocks of 24 outside lines incrementally.

ISDN PRI Improves on T1
A newer version of the T1 line is called ISDN PRI or Primary Rate interface. It uses the same T1 line but reserves one channel for signaling and switching. The other 23 channels are available as separate phone lines. ISDN PRI is popular with call centers because it provides faster call setup and teardown than the older T1 telephone lines. It also offers digital data ,such as Caller ID, that is not generally available on just T1 trunks. Like T1, though, multiple ISDN PRI trunks can be installed to provide as many outside lines as needed. Cost is competitive with T1 and most PBX systems come with the PRI interface already installed.

SIP Trunking, The Emerging Standard
While ISDN PRI is now the standard in commercial telephone trunking technology, an even newer technology is available to better support enterprise VoIP telephone systems. This is called SIP trunking. SIP is the switching protocol used by IP telephones and VoIP phone systems.

SIP vs T1
SIP trunks are also digital, but differ from T1 lines in that they are based on packet switching rather than time division channelization. Packet switching is the heart of all Ethernet networks that support computing. What companies are doing is replacing their old analog telephones with IP phones that connect to the same network as the computers. SIP trunks extend this connection out to the service provider for multiple telephone lines or a combination of voice and data.

Private Lines vs The Internet
Note that high performance SIP trunks are private lines between the user and the carrier and do not suffer from the vagaries of Internet broadband phone. SIP trunks often have the ability to also supply Internet service, but the telephone packets have priority to maintain high voice quality. SIP trunking is becoming popular for call center operations as companies replace their old PBX systems with newer IP PBX systems or choose to outsource the switching function to the cloud.

How to Choose
Which type of telephone trunking arrangement is optimum for your organization? Get some expert advice on the tradeoffs and competitive pricing from multiple carriers serving your location. Call now toll free (888) 848-8749 or enter your inquiry at Telexplainer.net

Choose Your Trunk, Choose Your Handoff

By: John Shepler

The telephone system isn’t what it used to be. Mostly that’s good. Technology has given us wireless mobile smartphones, enterprise VoIP, cloud hosted services and sophisticated call center operations. Many companies, though, can’t afford to shuck their considerable infrastructure investment in order to gain the advantages of the latest advancements. Is there any way to mash up the old and the new and have it work?

Indeed, there is. The magic is in something called a “handoff”. This is the interface between your telecom lines and your equipment. Let’s take a look at what type of handoffs are available to keep your phone system up to date.

In the beginning, “Ma Bell” offered one type of handoff. It’s the venerable analog POTS (Plain Old Telephone Service) line that is still popular today. Every phone was an analog phone and every line was an analog line. The handoff was in the form of a single twisted pair of copper wires. All the switching was handled by the public telephone system.

This type of connection still works well for businesses that need only a single telephone line. The phone plugs into a jack on the wall that connects to the telco POTS line. It’s the ultimate in simplicity. This arrangement supports both single wired handsets and the newer cordless phones. You can have multiple cordless handsets connected to a single POTS line.

A slightly more sophisticated business phone system allows multiple desk phones along with multiple outside lines. Each line is still an analog POTS line with its own phone number. It’s called a key telephone system because each phone has a button or “key” for each line. You can see the status of each line, typically 4 or 8, on the light for that line. You select the line you want by pushing the button for that line. You have to provide the switching intelligence for the system by answering the line that is ringing or selecting an unused line for calling out.

You can have as many analog phone lines as your key system will support. Since the lines are independent, there is no economy of scale with this arrangement. Two lines cost twice as much as one line, and so on. To gain a cost advantage, you need to move up to a trunk ing arrangement.

A trunk is a telecom line that supports multiple independent phone conversations. Originally, these were also analog using frequency division multiplexing. In the last 50 years, the old analog trunks have been replaced by digital trunks. T1 phone lines are a popular trunking system. Each T1 line supports up to 24 simultaneous phone calls carried on separate time multiplexed channels. The physical connection is two copper twisted pair. One is for transmit and the other is for receive.

Lets say you have a good size key telephone system with a dozen outside lines. You can provide those lines as individual POTS lines or with a single T1 line that carries all 12 phone lines with room to spare. The T1 line will likely cost less for a dozen lines. If you used all 24 channels, the cost savings would be even more dramatic. The issue you have, though, is how to connect a digital T1 line to your analog telephone system.

The answer is in a piece of interface equipment called a “channel bank.” This device converts between analog and digital signals so that both the phone system and the trunk line have the signal format and electrical characteristics they expect. As far as your phone system is concerned, the connection is exactly the same as if you had separate analog lines all the way to the phone company. This is called an analog handoff.

Another application for analog handoff is older in-house PBX (Private Branch Exchange) phone systems. A PBX is a key system with a brain. The PBX takes care of routing incoming calls and the bank of outside lines. When you dial “9” for an outside line, the PBX gives you the next available one. You don’t know or care which line it has selected. They all work the same.

Many PBX systems will accept one or more T1 lines directly. There is no need to go through the intermediate analog conversion using a channel bank. This is called a digital handoff. It may also be called a T1 CAS (Channel Associated Signaling) digital handoff or an ISDN PRI digital handoff.

ISDN PRI is a special type of T1 line that supports 23 simultaneous calls. What happened to the other channel? It’s used for signaling and switching to make the system faster and capable of slightly higher voice quality. Many PBX systems now have a connector for one or more PRI (Primary Rate Interface) trunks, as this is the most popular service for medium and larger phone systems.

Enterprise VoIP is the current technology being adopted en-masse by medium and larger companies. This replaces the analog or proprietary digital telephone wiring with network connections to the company LAN. The PBX is updated to an IP PBX that supports IP telephones. It also supports a packet switched phone line technology called SIP Trunking.

A SIP Trunk is digital, like T1 or PRI, but not separated into individual channels. Instead, the transmission protocol is Ethernet packets and a VoIP-centric switching format called SIP or Session Initiation Protocol.

An all-VoIP business telephone system would have IP phones and an IP PBX sharing the company LAN. A SIP Trunk connects the PBX to the telephone service provider. This is called a SIP handoff.

Another use of SIP Trunks is for cloud hosted VoIP services that provide the switching as well as connectivity to the public telephone network. With a cloud solution, you no longer have a PBX or IP PBX in-house.

Now, here’s where it gets interesting. You can often select your preferred phone trunk technology and specify the handoff you require. Just like T1 and PRI can be set up to provide analog handoff, SIP trunks can provide SIP, T1 digital, PRI digital, or analog handoffs. This means that your old phone system, with whatever interface it supports, can connect to modern networks and telephone trunking options. It often makes economic sense to continue using your current phone system until you can migrate to the latest technology.

Do you want to connect your current phones or phone system to the telephone service of your choice but aren’t sure how to make that connection? Find out what business telephone trunking options and pricing are available for your business location.

Fiber Optic Service FAQ, Part 2

Here are some more frequently asked questions and answers about fiber optic service for your business You may also be interested in the first list of fiber FAQs.

Q: What types of services are available over Ethernet fiber?

A: The Metro Ethernet Forum has standardized three popular services that are of interest to business users. Ethernet Private Line or E-Line is a dedicated point to point connection between two business locations or from your location to the Internet. Ethernet LAN or E-LAN provides a meshed network service that interconnects multiple locations. Ethernet Tree or E-Tree is a one to many connection popular with companies that distribute content to many subscribers.

Q: How do you connect multiple location LANs together

A: E-Line and E-LAN can do this easily. E-Line is appropriate for two locations to connect as a single bridged network. E-LAN makes sense for 3 or more locations, even those located internationally. E-LAN can make many separate LANs work like they are one larger network.

Q: What is Ethernet over SONET?

A: Most Ethernet providers offer a “native” Ethernet that powers their entire network. If you are in a location that can only get SONET, some carriers offer Ethernet that runs over the SONET fiber. From your prospective, this is the same as any other Ethernet over Fiber.

Q: Can Ethernet carriers interconnect?

A: Yes. The equipment that does this is called E-NNI or Ethernet Network to Network Interface. It allows service providers to seamlessly transfer network traffic back and forth. This allows both carriers to expand their service footprints to wider geographical areas.

Q: What are low latency fiber routes?

A: Most fiber networks strive to minimize latency or time delay between locations. Those advertised specifically as low latency routes are specially engineered to minimize the fiber route length using the straightest path available. They also minimize equipment along the route that can introduce additional latency. Low latency fiber services are in big demand for financial companies that deal in high speed trading.

Q: What is Metro Ethernet?

A: Metro Ethernet or MetroE is a fiber optic network that connects business and other locations within a limited geographic region, usually a single city or metropolitan area consisting of city and suburbs. MetroE connections can also connect to other locations nationally or worldwide.

Q: Does Ethernet support telephone service?

A: Ethernet is a great choice for enterprise VoIP phone service. A specialized service known as SIP Trunking connects your networked telephones or IP PBX to a distant service provider. The higher the bandwidth, the more simultaneous conversations can be supported. Traditional analog phones are better supported with analog phone lines or ISDN PRI service over T1 lines.

Q: Is Ethernet over Fiber distance limited like Ethernet over Copper?

A: No. Fiber offers unlimited transmission distance at any speed you wish. Most service providers have regional networks that serve multiple states or offer nationwide service. Some carriers connect worldwide using undersea cable between continents.

Are you interested in what fiber optic bandwidth service can do for your business? If so, get get instant online pricing up to 1 Gbps and complementary consultation with a bandwidth expert if you wish.


You may also be interested in reading Fiber Optic Service FAQs, Part 1 and Part 3.

Is MPLS The New Telephone Network?

The telephone network, as we’ve come to know and love it, is based on incremental improvements to the PSTN or Public Switched Telephone Network. This is a copper and fiber infrastructure that switches circuits to connect analog, cellular and digital phone calls from any party to any other party. Most business phone systems have depended on or mirrored the architecture of the PSTN to connect even their in-house calls. That’s all changing, with various technologies vying to become the next solution for connecting telephone calls.

What’s prompting the change? It’s not wireless. The cellular phone system was designed to be tightly integrated with the PSTN. The earliest cell phones were analog, with TDM and other digital multiplexed protocols following. What hasn’t happened yet is the wholesale transition to packet switched voice on the wireline or wireless phone networks.

Where packet switching, notably VoIP, has flourished is on private telephone networks set up by enterprises for their own use and on connections to the PSTN through the Internet to avoid the phone company local loops.

Why is VoIP such a big deal? More and more businesses are migrating their in-house phone systems to VoIP solutions. Part of the reason is the cost advantage of eliminating the separate phone wiring network in favor of using the corporate LAN to connect computers and telephones. Another reason is to avoid long distance toll charges by interconnecting business locations on a converged voice and data network. A third reason is features. IP telephones are really more like computers than the old desk sets. They can be integrated with business applications to provide things like “screen pops” of customer information based on who is calling.

The migration from circuit switching to packet switching was originally accomplished by replacing the traditional PBX (Private Branch Exchange) with an IP PBX. Think of the PBX as a small version of the PSTN switches that handle massive amounts of public traffic. The PBX resides on your premises and does all your in-house call connections so you don’t have to pay the phone company to make a call from one desk to another. You also need the capacity to make and receive calls with the outside world, so your PBX has to connect to the PSTN through one or more outside lines called trunks.

Trunk lines are bundles of telephone lines. Most businesses need more than one outside line. They may start off with a single analog business line and add more over the years. At some point it makes sense to consolidate all those separate lines into a single digital trunk that can carry up to 24 separate phone conversations.

Just because the trunk lines have been switched from analog to digital, doesn’t mean you are using VoIP. Yes, VoIP telephony is digital, not analog. But the digital protocol used by T1 and PRI digital trunks is time division multiplexed switched circuit, not packet switched IP. With an IP PBX, you can switch to IP telephones in-house and connect your IP PBX to the company LAN so that you don’t have to maintain the separate telephone wiring. Your connections to the outside world will still by the same analog or digital trunk lines to the PSTN.

Where you really cut the cord, so to speak, is when you replace those PSTN trunk lines with something called a SIP Trunk. This is a private line connection between your IP PBX and your telephone service provider. That service provider takes the place of the local telephone company and connects to the PSTN at their end. You can still make all the local and long distance calls you want, but perhaps at a considerable cost savings.

The alternative to the SIP Trunk is the Internet. The Internet connects literally from everywhere to everywhere. It is a massive public infrastructure that economy of scale makes very inexpensive. Connecting from telephone to service provider for residential users is done using the Internet. Many small businesses have also taken this approach to minimize costs.

The tradeoff is that voice quality over the Internet varies quite a bit. It depends on the capacity of your connection plus whatever else is happening on the Internet. Traffic jams called “congestion” can degrade voice quality with distortion and delay. One minute everything sounds great, the next minute the caller sounds garbled. If it gets really bad, the call may be dropped.

Many businesses can’t stand this variability of performance. They want the same quality of phone conversations they had with the PSTN, but with the advanced features and cost savings offered by VoIP. The technical answer has been to use a private line connection between your company and the service provider. These SIP trunks can support multiple conversations, even scaled for hundreds or thousands of simultaneous calls.

The latest development is cloud hosted PBX systems. Cloud computing offers businesses the opportunity to avoid capital investments and maintenance costs in favor of paying by the user by the month to use a cloud based infrastructure. Cloud computing has been extended to include telephone service through a cloud hosted VoIP or cloud hosted PBX system. All of your in-house switching and outside calls are handled through the cloud. You have IP telephones on your premises plus a gateway device that connects through a private line to your cloud service provider.

This is great for single business sites, but does the entire setup have to be replicated at multiple locations?

Yes and no. Yes, you still need your IP phones and gateway at each branch office or other location. However, you can route your calls through the same cloud hosted PBX. Now it becomes more sensible to connect all of your locations to your cloud service provider through a MPLS (Multi-Protocol Label Switching) network rather than pay the cost of a private line for each location.

MPLS networks are privately operated, as opposed to the public Internet, and maintain enough resources to simultaneous support the needs of all of their customers. This includes class of service tagging so that voice calls get the priority they need to maintain call quality. Each location simply needs a last mile connection, such as T1 or Ethernet over Copper, to the very large MPLS network. The network takes care of traffic routing between your locations and your cloud service provider where all the switching takes place.

One excellent example of where this approach is optimized is the XO Hosted PBX service offered by XO Communications. XO is also a network operator, so they can provide both the cloud PBX and the MPLS network to connect your business locations in one optimized system. This gives you one vendor to deal with if problems ever arise.

Sounds a little like the old Bell System, doesn’t it? You deal with a single provider who makes the connections to your phones and does the switching. In this case, you have a choice of vendors and a far richer feature set than offered in the old days of phone monopoly. Today’s cloud hosted PBX systems can include your wireless phones as well as your desk phones so that you only need one telephone number no matter where you are.

MPLS is a likely candidate to become the new telephone network. It supports hundreds or thousands of customers without interference or service degradations. Of course, there needs to be a way to interconnect customers on different networks. This is currently done by routing outside calls through the PSTN. Eventually, Network to Network Interfaces (NNI) may allow larger cloud PBX providers to peer traffic so that most of your calls will be on-net and not subject to toll charges. Even the PSTN may evolve to a very large MPLS network based on VoIP technology, abandoning the analog and TDM legacy technologies that have been the standard for the last century.

Is your company interested in more advanced phone services with potentially large cost savings? If so, get prices and features for enterprise grade VoIP and cloud services now.

Can You Save 50% With Unified Communications?

Have you noticed that your telephone expenses have grown right along with the expansion of your organization? Of course. In fact, they’ve gone up like crazy over the years. Have you seriously questioned why?

Why? Because you have more people on the telephone, of course. That’s the obvious answer, but it may be so obvious that you don’t look further. The fact is that not all telephone charges are created equal. Some are difficult to avoid and a necessary part of doing business. Others can be eliminated through the use of better technology. The technology that works this magic is called unified communications. Let’s take a look at a quick animation that explains everything...



Here are some important points made in the video and how they apply to you. Unified communications is all about merging your voice, data and video networks into one unified network. Many businesses can save money by doing this, even if they are smaller companies and even if they have only one location. Not mentioned is the hosted PBX solution that works especially well for smaller companies that don’t have a large IT staff.

The real cost cutting comes from consolidating the communications across multiple business locations. Some companies grow linearly with optimization every step of the way. Most don’t. If any of your growth has been from mergers and acquisitions, you can be pretty certain that your telephone network is not anywhere close to optimized. That’s probably true to some extent even if all you’ve done is add branch offices.

Why? Because the tendency is to have a phone system at each location. That means a stand-along PBX with trunks to the local phone company and different bills from different providers at each location. Then there’s the matter of communication among locations and back to headquarters. Chances are that this is done by making long distance phone calls and incurring long distance phone charges. Ding-ding-ding. You can just hear those telcos ringing the registers.

What’s better optimized? Moving your voice communications, i.e. telephone calls, from their own individual networks to your main corporate network that interconnects all locations. You need it for data anyway. Why not let voice packets piggyback on the same network?

What happens with this arrangement is that all your internal calls are free of charge. The phone company can’t charge you if you don’t use their network. So, stay off the PSTN (Public Switched Telephone Network) until you absolutely have to use it. That’s for outside calls to other companies or your own customers.

By letting a major competitive carrier, like Level 3, be your network and phone service provider, you can get by with a single IP PBX located somewhere on the network to route outside calls through one set of PSTN trunk lines. Level 3 has the advantage of being licensed as a competitive phone company in all 50 states, so they can get you local numbers wherever you want to establish a presence.

Is it really possible to save 50% of your phone bill by using unified communications? It can be that lucrative. How much can your operation save? Get competitive quotes for unified communications SIP trunking for all your business locations and see just how far your eyes bug out at the answer.

CAS vs PRI Voice Channels

T1 telephone trunk lines are popular with PBX and IP PBX phone systems. Most current equipment offers an interface connection so that you don’t need separate a CSU/DSU box to connect to the line. What you may not know is that there are two type of T1 telephone lines available. One is CAS and the other is PRI, also known as ISDN PRI.

T1 CAS is the original design for T1 lines used as telephone trunks. The line is channelized or divided into 24 separate segments of 8 bits each sampled at 8 Kbps. Multiply 8 bits by 8 Kbps and you get 64 Kbps, which is the capacity of one T1 channel or DS0. The designation DS0 stands for Digital Signal level 0, the basic building block of a T1 line.

What goes into a DS0? It’s one digitized telephone call. The process of converting from analog to digital is called PCM or Pulse Code Modulation. The 8 bits are enough to represent 256 different voice levels and provide excellent voice quality.

A collection of 24 channels of 8 bits each strung together end to end plus 1 extra bit defines a T1 frame. The extra bit is used to synchronize the equipment so that it knows where the frame starts. Hence, the designation “framing bit.”

Now, here’s where CAS comes in. Notice that each of the telephone channels is filled up with digitized voice. The framing bit is occupied in synchronizing the line. So, how do you communicate dialing and switching information? The dialing is handled by transmitting the DTMF dial-tones through the voice channels just like you would over an analog line. Knowing whether the channel is on-hook, off-hook, ringing, etc, needs to be handled by some extra bits that aren’t designed into the system. The way this is done is by “robbing” one bit from each channel periodically to create a signaling channel. This degrades the voice channels by such a small amount that it isn’t noticed.

The robbed bit signaling technique combined with DTMF dialing means that each channel is responsible for its own operation. This is what is called Channel Associated Signaling or CAS. Another name for this is in-band signaling. Each channel on a T1 line is equivalent to one analog telephone line. There are separate transmit and receive paths on the T1 so that you can talk and listen at the same time. This is full duplex operation.

Here’s something interesting. You don’t need a PBX system to use a T1 line to bring in multiple business phone lines. Instead, you buy a device called a Channel Bank that converts 24 phone lines to one T1 line. The channel bank handles all the interfacing and conversion back and forth between analog and digital protocols.

The other type of T1 telephone line that has become even more popular than T1 CAS is T1 PRI or ISDN PRI. ISDN is a set of digital standards that include a low speed and a high speed option (BRI and PRI). PRI stands for Primary Rate Interface. You might think that it is something completely different from T1, but actually PRI is just a reorganization of the T1 channels.

With ISDN PRI, 23 of the 24 available voice channels are kept exactly the same as T1 voice channels, but are called B channels or Bearer channels. The remaining channel is called a D channel or Delta channel, sometimes called a Data channel. With ISDN, all the control and signaling is assigned to the D channel. There are no robbed bits from the voice channel. What that does is speed up the dialing and switching, an important feature for high volume call centers. The other advantage gained by having a D channel is that it can be used to supply digital data, such as Caller ID. ISDN signaling is known as CCS or Clear Channel Signaling to distinguish it from CAS. This is also referred to as out of band signaling as opposed to in-band signaling.

The nice thing about T1 lines is that they have well established standards to support both voice and data services. If you need telephone trunk lines for an in-house PBX or IP PBX systems, chances are that some configuration of T1 line will do the job. You may be surprised by how competitive T1 prices are now. Check T1 and ISDN PRI prices online to compare with your other telephone service options.

Is HPBX Your Next PBX?

It’s almost back to the future, to coin a phrase. Companies nationwide are getting rid of their phone switching equipment and going back to service providers, what we used to call telephone companies. Only the phones and the telephone trunk lines remain. Is technology reversing itself or is there something new going on here?

Make no mistake about it, telephony today is different from the telephone service of yesteryear. But there are similarities, too. What companies have found is that building and maintaining little telephone companies in-house entails a lot more cost and bother than you might expect. If that’s true, though, why did they ever leave good old Ma Bell in the first place?

One problem with business phone service versus what you have in your home is that there are lots and lots of phones. If you only have one or two lines, you probably have just one or two phones. It’s likely that each phone is tied to a particular phone line. Perhaps you have multi-line phones where each line has a switch or “key” so you can select it. Some small offices have only a single phone set one one line and use a second line to connect a FAX machine or credit card terminal.

So what’s the problem with having so many phones? It’s pretty likely that by the time you have a few dozen phones, your office facilities are so spread out that people can’t lean over to the next desk and have a conversation. They either have to get up and walk down the hall or make a phone call. If each phone has its own line, then those calls will go through the phone company and you’ll likely pay a charge. If you want to talk to someone in a branch office in another state, you’re surely going to pay long distance charges.

What companies really wanted was something of an intercom feature, where they could just dial a few digits and get to another phone in-house. To accomplish that, they bought PBX or Private Branch eXchange equipment. The PBX is the device that connects phones and also managed outside lines as needed. All the phones connect to the PBX and the PBX connects to the phone company, but only for calls leaving the premises.

The local telephone companies offer a service called Centrex (Central Office Exchange) to compete with the PBX. The switching equipment is kept at the central office, like always, but the system functioned more like a PBX. The Centrex system based on the individual copper pair from each phone to the CO is now being replaced by HPBX or Hosted PBX service.

What’s different about HPBX is that it is a VoIP phone system. Communication is over a WAN network connection called a SIP Trunk. This frees the user from being tied to a particular local phone company by those ubiquitous twisted copper pair. Now any service provider anywhere in the world can be your phone company as long as you can get a digital connection between their facilities and yours. What you need in-house is IP phones, also called SIP telephones, connected to your converged voice and data network. Your service provider hosts the PBX switching function with termination to the public switched telephone network as needed.

Are you ready for a phone system upgrade or merely concerned that what you are doing now costs more than it could? Get competitive quotes for hosted PBX telephone systems, some of which include new phones as part of the service fee.

VoIP Trunk Service Providers

Any business with more than a few outside phone lines knows that trunk lines are the way to go. The next question is what type of trunk service to get. You might think that with a VoIP telephone system, the obvious choice is SIP Trunking. But is it? Take a closer look at what’s available and then decide.

The idea of telephone trunking originated with the phone companies back when Ma Bell ran the industry. When phones were new, a couple of wires were all you needed to connect from your location to the local phone company. Then everybody wanted a phone and businesses started installing switchboards to handle all the lines they needed. You know those old-timey photos of phone line congestion in the cities. That’s what happens when you build out one line at a time.

The mass of subscriber lines was gotten under control using multi-pair cable, often buried. But long distance lines between switching offices were another matter. The more simultaneous calls you carried, the more wires were needed. That gets expensive fast when you’re talking about dozens or hundreds of miles. Wouldn’t it be nice if one pair of wires could carry multiple conversations?

That’s the origin of the trunk line. The early systems were set up like radio stations on the dial, except over wires. Each call modulated its own carrier frequency that was spaced far enough in the spectrum from adjacent carriers so that they wouldn’t interfere. This was analog carrier telephony. The switch from analog to digital technology came with the T1 line. It’s been around for at least half a century and is still going strong.

T1 telephone trunks are divided into 24 separate channels, each transporting one two-way telephone call. All the dialing and switching is done on these channels, just as it would be on analog phone lines. You can get devices called channel banks to convert T1 to and from 24 analog phone lines at your office. The T1 line itself is two twisted pair running from your building to the nearest phone company central office.

The advantage of T1 lines as telephone trunks is that save a lot of wire and can save cost, too. There is no economy of scale when you buy your phone lines one at a time. Soon you have a dozen or two at the price of a dozen or two times the cost of one line. If you convert all those lines into a T1 telephone line (trunk), you’ll generally save money even if you only use half the capacity of the T1. If you need dozens of lines for your call center, T1 can save you a bundle.

Chances are that you won’t need a channel bank unless your phone system is completely analog. Most PBX systems have T1 ports already installed. Even the new IP PBX systems designed for VoIP telephones usually have T1 ports where you just plug in one or more T1 lines for your outside telephone service.

A closely related service that is even more popular than T1 telephone trunks is ISDN PRI. This service runs on a T1 line and is very similar to a T1 trunk. The difference is that only 23 channels are used for individual phone lines. The remaining channel is used for all the dialing, switching and data such as Caller ID. The switching is faster than with T1 telephony and most everyone wants Caller ID anyway. The port for this is called a PRI, ISDN PRI or T1 PRI an it is likely installed in your system now.

The other digital trunk option that is becoming popular thanks to VoIP is the SIP Trunk. SIP is the switching protocol used with IP telephones in a VoIP system. A SIP Trunk, which might also be carried on a T1 line, is not broken up into channels. Instead it is more like your local area network that transports Ethernet packets.

This is one of the big advantages of a SIP Trunk. It can connect directly to your network without having to convert from one protocol to another. In fact, just like your network carries both VoIP phone traffic and computer data traffic, a SIP Trunk can provide both telephone and broadband service from your service provider. This is the preferred arrangement, as it allows the provider to establish class of service controls to maintain voice quality regardless of other network traffic.

As you might suspect, an IP PBX system works well with a SIP Trunk. But SIP trunks can also be ordered with customer premises equipment that offers a T1 or ISDN PRI digital handoff or even analog phone lines.

Which type of telephone trunking service is right for your business? Compare prices, availability and options of T1, PRI and SIP Trunks to see what makes the best economic as well as technical sense for your particular situation.



Etching of phone lines in New York City circa 1890 courtesy of Wikimedia Commons.

What is a PRI in VoIP?

We tend to think of VoIP as a “new generation” phone service based on IP technology unrelated to the historical public switched telephone network. Well there’s some truth in that, but no matter what you implement you’ll still be dealing with the good old PSTN. The bigger your company or organization, the more “outside” phone lines you’ll need. You should take a close look at ISDN PRI to make the connection to all the phones that are not part of your enterprise VoIP telephone system.

What is a PRI? It stands for Primary Rate Interface. That’s telephony talk for a particular standard related to another telephone industry term, ISDN. ISDN is the Integrated Services Digital Network. There’s a history to the development of ISDN that relates to the once lofty ambition of replacing all analog home and business phone lines with digital versions. You may not have heard of this, as it fizzled when broadband Internet came along and usurped the data role intended for ISDN. Even so, the business version persists and is more popular now than ever. That’s what’s called PRI or ISDN PRI or even T1 PRI.

Why T1 PRI? It’s because ISDN PRI is physically transported on a T1 line. T1 is another telephone industry standard widely used in business for dedicated Internet and point to point data connections. T1 lines have the advantages of being provisioned on copper wires so you don’t need fiber optics installed. They can be extended to nearly any distance, are highly reliable and reasonably priced. The pricing has gotten really attractive lately due to all the competition in the industry. With all this going for it, T1 makes a great choice to carry PRI.

What’s different between a regular T1 line and a T1 PRI line? The line speeds and voltages are the same. What differentiates a PRI is how it is organized. Instead of a big chunk of bandwidth, ISDN PRI is set up as 23 channels that each represent one digital telephone line. A 24th channel is used for signaling and data such as Caller ID. It’s an upgrade to an older T1 telephone standard that was set up as 24 phone channels and no Caller ID.

The beauty of bringing in an ISDN PRI line or “trunk”, as it is called, is that you get 23 outside phone lines coming in on a single digital line. It’s a lot more compact and is almost always cheaper, usually a lot cheaper, than dealing with 24 individual analog business lines.

The interface is also generally very easy. Most PBX and IP PBX telephone systems either come with ISDN PRI capability or offer it through a plug-in module you can buy. All the circuitry to convert between 23 individual phone lines and the PRI digital trunk are implement on that circuit board. You simply plug-in one or more ISDN PRI lines and you have outside phone lines and a lot of them.

But why would you connect a T1 PRI to a VoIP phone system rather than keep it 100% VoIP? The simple explanation is that the rest of the world isn’t serviced by VoIP or at least the same VoIP provider. The only thing universal is the PSTN, where you can dial any number and get connected to any telephone in the world. Your enterprise VoIP phone system can save you a bundle on internal calls that stay on your own network. You can also buy a SIP Trunk that connects you to a telephone service provider completely in IP or Internet Protocol. But, guess what happens at that service provider when you want to call an outside number? That’s right. You’ll be switched through to the ISDN PRI lines that connect them to the public phone network.

Which is the best deal for your company when it comes to analog (POTS) phone lines, ISDN PRI or SIP trunking? Why not let an expert consultant get you competitive quotes for these various options so you make an informed decision? The service is fast, easy and free.

Why Are VoIP and SIP Trunking So Popular?

If your old PBX system is getting long in the tooth and it’s time to start considering a replacement, you’ll do well to look into replacing that PBX with an IP PBX and those phone lines with a SIP Trunk.

Why are these new technologies catching on so fast when traditional telecom equipment and analog or ISDN phone lines work just fine? The answer is new features combined with cost savings while maintaining call quality.

You might be getting a headache right now, thinking about the capital investment and installation expense required to change out all those phone sets that are still getting the job done. Breathe easy. You don’t have to swap out any of your old phones unless you want to.

There are good reasons why you might like a new VoIP SIP phone. For one thing, they plug right into your computer network and don’t need separate telephone wiring of their own. You manage them like any other device on the network. Since a SIP phone can plug into any network jack just like a PC, it’s much easier to manage moves, adds and changes. You want to move to a different office? No problem. Just take your phone with you and plug it in to the network jack in the new office. The phone still has its own MAC address that identifies it as yours, so it doesn’t matter where on the network it sits.

But what about the old phones you want to keep? Just connect their phone wires to your new IP PBX. You’ll need to order interface cards with FSX ports to make the connections, but the IP PBX doesn’t mind a bit. You can even have a mix of SIP phones connected to your LAN and analog phones connected to FSX ports. The IP PBX will treat them all as individual telephones. Of course, the SIP phones may have extra features like displays or the ability to coordinate with computer terminals, but they’re still telephones.

By the way, you don’t necessarily need to have a PBX system on your premises anymore. VoIP has opened the door to hosted PBX, where the call switching hardware is located at an offsite supplier who provides telephone services at an attractive price. It’s a way to avoid the often hefty capital investment required for a new in-house IP PBX system.

VoIP telephony has become popular in business environments with lots of phones, primarily because of the ability to converge the LAN network to support voice as well as data. That makes it possible to keep the phone system truly off the public network for all locations that are reached by the corporate LAN. It’s only when you need to talk to outside parties that you need public phone lines. Or do you?

Yes, you do. But you don’t have to provide those lines yourself. What a SIP trunk does is extend your internal network to a service provider who then connects to the public phone system. Economy of scale generally means that telephone calls over a SIP trunking service are less expensive that terminating them yourself to analog phone lines or ISDN PRI trunks connected to the phone company. SIP trunking services also generally provide dedicated Internet service over the same SIP trunk. After all, it is just a network extension. As long as quality of service is maintained, you can get your telephone and Internet services from the same provider over a single SIP trunk and realize a cost savings.

Are you interested in exploring the expanded performance and cost savings available with VoIP and SIP Trunking services? You may be surprised at what you can get for much less than you are paying now. Enter a quick Enterprise VoIP quote request now with a brief description of your needs and you’ll get a fast response and personalized service.

TelePacific’s SmartVoice Trunking Offers Telephone Smarts

TelePacific Communications has a clever and sophisticated solution for small and medium size businesses that need telephone and Internet service. It’s a SIP trunking solution that offers both voice and data on a single telecom line. What distinguishes their SmartVoice service is that it can accommodate different kinds of business telephone systems and offers a lot more traffic capacity than Integrated T1 lines.

SIP trunking is an IP-based transmission line designed to support enterprise VoIP telephone systems. SIP is Session Initiation Protocol, the signaling technology used by many IP phone systems. Since IP networks transport voice and data packets equally well, many SIP trunking providers offer a combination of telephone and Internet service on the trunk line.

TelePacific’s SmartVoice Trunking also offers a combination of telephone and Internet service. The system is set up so that any bandwidth not being used for telephone calls is dynamically allocated to Internet bandwidth. If another phone call takes place, that call gets a priority on the bandwidth it needs to ensure voice quality.

Now here’s something different. An Integrated T1 line will do this, but only up to its capacity of 1.5 Mbps. That’s typically no more than a dozen simultaneous phone calls with 750 Kbps of broadband Internet. SmartVoice Trunking bonds multiple T1 lines together to create a single SIP trunk line. Up to 4 T1 lines can be bonded to create a path bandwidth of 6 Mbps.

The significance of all this bandwidth is that larger businesses or telephone-intensive operations, such as customer contact centers, can have up to 48 simultaneous phone conversations through their IP PBX and SIP Network connection. Perhaps you don’t need that many phones, but do need the bandwidth for broadband Internet access to support many users. The Dedicated Internet Access on the SmartVoice trunk gives you the bandwidth you need without the necessity of paying for completely separate telephone and Internet lines.

SmartVoice also supports a wide variety of business telephone systems. The latest IP PBX phone systems are supported, of course, but so are standard PRI and CAS trunks for traditional digital PBX systems. You can even connect analog handsets or your key telephone system with capacity for anywhere from 4 to 24 outside lines.

What sort of advanced features does SmartVoice support? Caller ID is standard. You can also get up to 100 DID or Direct Inward Dial numbers so that each employee has their own phone number and there is no need to go through a receptionist. A feature set just added is hunt groups. With hunting, if one person doesn’t answer the call it will go on to the next person in line on a linear or circular pattern. Circular hunting allocates incoming sales calls to the sales staff on a round-robin basis so that every sales person gets a fair share of the prospects. There are other patterns you can set also.

Does this sound like the kind of telecommunications service that would benefit your company? If so, talk to an expert consultant and get a quick quote on SmartVoice and other cost effective voice and data solutions.

Private Branch Exchange Connections

Private Branch Exchanges, also known as PBX telephone systems, are the most popular business phone technology for medium and large organizations. Recent technical advancements have brought PBX prices down to the point where even small companies can upgrade from hard wired analog phones or key telephone systems. If you are in the market for a new PBX system or want to see what's available, you can contact the VAR Network to get an idea on prices and system options.

In addition to the hardware, Private Branch Exchange systems need connectivity. There are a wide variety of options available, each with their own cost and performance advantages. The most basic connection is called an FXO or Foreign Exchange Office. That's another way to say analog telephone line to a phone company central office or CO. These are individual twisted pair connections that provide dial tone and local phone service. They may also be set up for long distance calling and toll free numbers. For one to a few lines, it's hard to beat good old analog lines for cost and voice quality.

Once your business has grown to the size where you are using more than a half-dozen outside lines, it's time to consider trunking services. A trunk is digital phone line that carries multiple conversations simultaneously. The most popular digital trunk line is ISDN PRI, which stands for Integrated Services Digital Network Primary Rate interface. That mouthful is jargon for a T1 line that offers up to 23 outside lines plus faster call switching and Caller ID. Another version of T1 telephone service offers 24 phone lines, but slower call switching and no Caller ID information. ISDN PRI lines usually plug into an interface card on your PBX system, a common option.

The reasons to go with ISDN PRI service are high voice quality at lower cost than multiple analog lines. This type of service is very popular with corporate users and call centers. Each line can be configured for incoming and/or outgoing calls. DID service can give each employee their own telephone number without having a separate outside line for every number. The system assigns lines as needed. Larger organizations can get multiple ISDN PRI lines for greater capacity.

The newest PBX systems go by the designation IP PBX. This is enterprise VoIP telephony. IP PBX systems can have individual lines run to each phone or use SIP handsets connected to an Ethernet network. SIP is the switching technology of VoIP. A SIP trunk can provide outside phone lines and even Internet service as an option to the combination of ISDN PRI trunking plus T1 dedicated Internet access.

With all these options, how do you go about choosing the right service for the performance and capacity you need? An easy way is to get free comparison pricing and discussion of your needs with a expert consultant from Telarus through the Shop For T1 service. Even if you already have a phone system that you are happy with, Telarus can likely save you money on your monthly business phone bills.

T1 Phone Lines Offer More For Less

Once your business gets big enough that the telephone bill is a significant part of your monthly expenses, you may be ready for a higher volume, lower cost service. That's especially true if you have started a dedicated contact center for your customers or have grown to a dozen or more outside lines.

The service you'll be interested in is called a T1 telephone line. A T1 "line" is a digital telephone trunk as opposed to a single telephone line. What trunk means is a group of phone lines all bundled electronically into a single line. If you order your phone lines one at a time, as most growing companies do, you'll get individual analog lines with local dial tone and perhaps long distance service. Each line is independent of the others. You select the line you want with a multi-line phone or key telephone system. Or, your PBX system will automatically pick one for you.

T1 telephone lines come bundled up to 23 or 24 to a T1 line. Each line is still independent and can be configured for local and/or long distance service, incoming or outgoing or both, depending on your needs. What T1 telephone service does is offer a volume discount compared to just adding more and more analog phone lines.

Do T1 lines connect to your phones the same as conventional analog phone lines? Not exactly. You need something to perform the conversion between analog and digital formats. If all you want to do is consolidate a bunch of analog phone lines that feed a bunch of analog handsets, a device called a "channel bank" will do the job for you. The T1 line feeds into one side of the channel bank and up to 24 individual phone lines come out the other side.

Most of the time, if you have a dozen or more phone lines you probably have a PBX telephone system in-house. The PBX or the newer IP PBX systems have gotten small and inexpensive compared to the closet full of equipment they used to be. Many newer systems come with a T1 line interface or can be ordered with that configuration. If your existing PBX system doesn't have T1 line capability, you can usually order a plug-in card that will make the connection.

There's something else you need to know about T1 phone lines. There are two types. The original configuration is a channelized T1 line with 24 individual channels, one to transport each telephone line. A newer arrangement is the T1 PRI or ISDN PRI. PRI stands for Primary Rate Interface. This is the most popular version of T1 phone service because it offers up to 23 telephone lines plus Caller ID information and faster call switching. Most PBX and IP PBX phone systems can handle T1 PRI as well as conventional channelized T1 lines.

Because of their economy of scale in combining multiple phone lines into a single digital trunk, T1 phone lines can offer you more capability for less money. How much more for how much less? That depends on how you want your service configured. There are often limited time special offers from competitive carriers that can make the line lease cost even more attractive. Find out how much you can benefit from the most competitive offers on T1 phone lines now.

Toshiba Strata CIX Does SIP Trunking

The standard telephone line connection for PBX business phone systems has evolved from multiple analog telephone lines to T1 and T1 PRI digital trunks. Since Enterprise VoIP became popular, an all-IP trunking option called SIP Trunking has also emerged and is being supported by more and more carriers. With SIP trunking, there is no need to terminate IP PBX phone calls back to the PSTN (Public Switched Telephone Network) in-house. Instead, the SIP Trunk carries voice and Internet data packets to a service provider who does the termination. Economy of scale allows SIP Trunking services to offer lower cost voice and data connections.

Toshiba is embracing this technology change in its Strata CIX IP Business Communication Systems. They've integrated SIP trunking support into this product line so that a separate VoIP gateway is not needed. The SIP trunk, usually a private point to point T1 data line, connects to the IP PBX through an MIPU interface card. The far end of the connection is hosted by the SIP service provider who manages QoS or quality of service so that voice packets get priority over data packets.

SIP trunking is a rapidly growing service that may one day completely replace the traditional PSTN and its SS7 switching system. SIP trunking providers can today offer direct IP to IP phone connections to their customers, bypassing the PSTN termination process and its attendant costs entirely. If enough companies and individuals connected to the same VoIP provider or if VoIP service providers provided low cost peering, most calls might just stay in the IP domain. Private networks such as SIP trunks have the ability to maintain call quality, a problem when trying to use the public Internet as a voice trunking service.

Toshiba's Strata CIX product line comes in a family of versions to support businesses from small shops through medium size enterprises. The Strata CIX 40 handles 4-11 trunks, 8-16 digital telephones, 1-2 analog station ports, and 8-24 IP channels. The largest system, the Strata CIX 670, handles 264 trunks or 560 station users and combinations up to 672 ports.

Toshiba's SIP trunking capability currently supports SIP carriers Cbeyond and American Broadband Services, with others to be added soon. Other SIP trunking carriers support a wide variety of PBX and IP PBX telephone systems through their own customer premises interface boxes.

If you are interested in upgrading or expanding your IP Phone system, we can connect you to our network of qualified business telephone system dealers specializing in Toshiba and other major brands.

Or, if you are happy with your phone system but would like to explore the cost advantages of SIP Trunking or competitive T1 / PRI service providers, our team of voice and data experts would love to get you quotes on the best telecom services for your business location. No cost. No obligation.

Unified Communications Merges Everything

Convergence is a trend in enterprise networks, often focused on migrating telephony to the corporate LAN using VoIP. But the ultimate goal of unified communications involves integrating all electronic communications. That encompasses wired telephony, voice messaging, video conferencing, data networking, network security, VPN and wireless access.

Interestingly, Cisco already has a platform that will do all of this and more for the smaller business. It's the Cisco Unified Communications 500 Series. The basic solution includes telephony support for 8 IP phones, 4 FXS analog phones and 4 FXO analog trunk lines, plus support for SIP trunking. It has integrated voicemail and an auto-attendant, making it a full-featured small office PBX phone system.

So far this sounds like a typical small office IP PBX system. But the 500 series platform goes further. The antenna implies wireless communications. In this case it's an 802.11b/g wireless access point that supports wireless LAN IP phones as well as wireless data devices.

Connection to the WAN or Wide Area Network gives you broadband Internet access with full security via a Cisco IOS Firewall that supports point to point VPNs. Use these Virtual Private Network connections to include home workers or employees operating remotely. You can also easily expand LAN access inside the office by adding a Cisco Catalyst Express 520 Switch with 8 additional ports of 10/100 Mbps PoE (Power over Ethernet). This switch comes configured to work immediately with the 500 series.

With this system, called the Cisco Smart Business Communications System, you have up to 16 computer workstations, IP security cameras, or IP phone sets, a data/voice wireless access point, secure WAN (broadband Internet) access, secure VPN communications to remote locations, an in-house telephone system that connects to the PSTN and supports FAX machines and other analog devices, plus simplified set-up and management built-in. It's a single box that supports the complete small office communications needs.