Connectivity Expansion With Multiple T1 Lines

T1 lines have been excellent network connection options for decades. They still are if your bandwidth needs are modest. But what do you do when 1.5 Mbps just won’t cut it anymore? Is it time to say goodbye to your faithful T1 line?

Wait! Not so fast. Those T1 lines have a lot of untapped potential. It’s simply time for a technology upgrade.

That upgrade is called “bonding.” As the name implies, bonding is a process of combining the capacity of multiple T1 lines so that they act as one larger bandwidth service. This is typically done using a managed router. The carrier’s side of the router has interface cards for two or more separate T1 lines. You plug into a single connector that delivers the combined bandwidth of all those T1 lines.

What level of bandwidth is reasonable to expect? Dual bonded T1 gives you 2 x 1.5 Mbps or a total of 3 Mbps. Triple bonded T1 produces 4.5 Mbps. Quadruple bonded offers 6 Mbps. You can bond 5 T1 lines for 7.5 Mbps, 6 lines for 9 Mbps, 7 lines for 10.5 Mbps and 8 lines for 12 Mbps. Generically, this is designated as NxT1 where N is the number of T1 lines involved.

Not all of these options will be available in any particular area. Two factors determine how much bandwidth you can get with multiple T1 lines. First is the equipment available at the central office where your telephone wire bundle terminates. This bundle consists of many twisted pair, perhaps as many as 50 pair, all in a single cable. That cable runs underground or overhead on telephone poles to get from your building to the telco office. Multi-pair bundles are almost always installed to business locations because they very often need multiple line telephone service.

The equipment is important because there have to be connections at both ends of the copper cabling for the bundling to work. There is a managed T1 router with multiple line cards installed in the telecom closet in your building. There is a complementary piece of equipment in a rack at the central office to connect to the far end of those T1 lines.

Assuming that the carrier equipment is in place, the limiting factor in bonding multiple T1 lines is the availability and quality of the extra copper pairs in the bundle. Some cables may not have 8 unused pairs available. That’s especially true if the building supports multiple businesses, all using several phone lines or more. Other cables may have vacant pairs, but they have bridging connections or quality problems that don’t support reliable data transmissions. In some cases, adjacent pairs may have too much cross talk to both carry T1 signals without data corruption.

A final issue is cost. The price of T1 lines has come down dramatically over the years. If you haven’t checked pricing since you signed your contract and renewed it a couple of times, you may be shocked at how little it costs to maintain T1 service these days. Some companies find that they can easily upgrade to 2xT1 or 3xT1 and not pay any more in monthly least costs. Otherwise the cost of bonded T1 service is the single T1 line times the number of lines you want to connect. There’s no real economy of scale.

If you still need 10 or 12 Mbps but the cost of 7 or 8 T1 lines is too much for the budget, you aren’t out of luck. A competing technology called Ethernet over Copper (EoC) can typically give you twice the bandwidth for the same dollar. EoC uses the same copper pair you would otherwise use for T1 but can support higher bandwidths, perhaps 15 Mbps, 20 Mbps or more. Unlike T1, Ethernet over Copper is distance sensitive and only works well for locations near the CO.

Would you like to upgrade to higher bandwidth business connections without the expense or inavailability of fiber? Get pricing and bandwidth options for multiple T1 lines and competitive EoC options now.



Note: Photo of multipair cable courtesy of Wikimedia Commons.

Can SIP Trunking Supplant ISDN PRI?

Companies large enough to use multiple business telephone lines are good candidates for digital trunk lines. It used to be that you needed a dozen or two outside lines before digital trunks made sense. Now just a few lines plus broadband Internet can make telephone trunks attractive.

Just what is a telephone trunk? It’s a collection of telephone lines, all bundled together. We tend to think of landlines as individual connections. One analog landline is a single pair of small plastic coated copper wires twisted together in a spiral. This isn’t just to keep related wires in pairs to form a complete circuit. The twisted form causes induced magnetic fields to cancel out over distance. This reduces the amount of hum, noise and crosstalk from other telephone lines.

Companies that have a few outside lines often have what’s called a key telephone system. The “key” refers to the line select buttons on the phones themselves. It’s up to the user to note which lines are being used by observing an indicator light for that line button. Unlit line button are free lines that you can use to call out. Each line is an individual analog phone line. They generally come-in through cables of 25 pairs or more called binder groups. You might think of this large cable as an analog trunk line.

The impetus for digital trunk lines is the opportunity to use less copper wiring to transport the same number of phone calls. Stretching miles of binder cable from your location to the telephone company central office (CO) costs a goodly sum. That’s nothing compared to the cost of running long distance lines dozens or hundreds of miles. The first digital trunk was the T1 line. It uses multiplexing to create a stream of 24 channels in 24 serial timeslots. Each channel represents one telephone line. The T1 trunk itself uses 1 or 2 pair of wires versus 24 pair for an equivalent analog trunk.

A T1 telephone trunk can be connected to a channel bank that converts between the digital line and analog telephones. This allows companies with key telephone systems to lease a T1 line at lower cost than 24 separate analog phone lines. A more popular use for this many lines is to connect to an in-house PBX or Private Branch Exchange. The PBX system automatically manages all the outside lines and offers 3 or 4 digit dialing for in-house calls.

An upgrade to the T1 telephone line is the ISDN PRI trunk. The two standards are very similar. ISDN PRI stands for Integrated Services Digital Network Primary Rate Interface. This is quite a mouthful, but is part of an industry standard that has become very popular for business telephony. The difference between T1 telephone and ISDN PRI trunks is that ISDN reserves one of the channels for switching and data. ISDN PRI offers 23 phone lines plus Caller ID, ANI, and much faster switching. Both T1 and PRI interfaces are common on modern PBX phone system designs. They are either a standard features or can be added with a plug-in card.

What’s the advantage of T1 telephone or ISDN PRI to the business user? They cost less than ordering 23 or 24 separate analog phone lines. The person in the office taking a call on their desk phone can’t tell how the phone lines come into the back room. The manager paying the monthly phone bill sure can.

There’s an even newer form of digital telephone trunk available now called the SIP Trunk. SIP refers to the signaling system used by VoIP telephones. It is computer network based rather than telephone industry based. This allows voice and data to be combined or “converged.” Once you have a converged network, you no longer need separate LAN and telephone wiring. Everything in on the LAN.

What the SIP Trunk does is connect your LAN to your phone service provider. This is a long haul private point to point connection so your “phone company” can be located anywhere. It doesn’t matter where those twisted pairs in the ground go. On the network, one location is as close as another.

The other advantage of SIP Trunking is that it can transport both telephone calls and broadband Internet service at the same time without one interfering with the other. Telephone calls have priority in this system so that voice quality is preserved regardless of what is happening on the Internet. Your calls never actually go on the Internet. The simply share a trunk that transports both.

This offers a terrific advantage for smaller companies. Most every business now uses both telephone and Internet service, so why not have them both provided on a single line instead of two? This maximizes the efficiently of the trunk line and saves money for the business user.

ISDN PRI is still wildly popular as a trunk line for PBX systems. Newer IP PBX systems will support both ISDN PRI and SIP Trunking. Why make the change? Compare prices and features to see if SIP Trunks can save you significant money. Smaller companies that can’t possibly imagine using 23 outside phone lines will likely find that SIP Trunking can be scaled down to the number of lines they really need and that’s all they have to pay for. The option of having broadband delivered on your SIP Trunk is also a plus for smaller companies that don’t need the whole trunk for telephone lines.

A potential game changer is the rise of hosted PBX systems or PBX in the cloud. Hosted services connect via SIP Trunk and there is no PBX equipment or phone lines at your location. You pay per user by the month. This offers tremendous flexibility, as you can always order up more “seats” when business increases and you need them.

Are you interested in new business telephone service or are at the point where your current phone system is out of capacity or too costly to maintain? Don’t lock in your decision on how to proceed until you check the latest prices and features of ISDN PRI, SIP Trunking and Hosted PBX services.

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.