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

PRI over Cable Cost Savings

Many businesses use ISDN PRI trunking to provide phone service for their organizations. The original motivation to move from analog business lines to PRI was the cost savings that T1 technology offered. Now there is a newer and even better cost option called PRI over Cable.

Regardless of the delivery technology, ISDN PRI is a well-established standard for bundling up to 23 business telephone lines on a single digital cable. Why 23? It’s because T1 lines were designed to have 24 channels, each capable of transporting one high quality digitized telephone conversation. One channel is reserved for signaling and Caller ID, leaving 23 channels available for phone calls. Each channel is equivalent to one analog phone line. By bundling them, you can almost always save money over ordering 23 individual phone line.

What’s more, nearly all modern PBX telephone systems and many key telephone systems support the ISDN PRI standard. There is a PRI jack on the back of the system or a plug-in accessory card. Many larger business phone systems accommodate multiple PRI lines so you can have 46, 69, 92 or more outside phone lines if your company is large enough to need this many.

ISDN was designed around T1 lines, but there is no reason that more modern packet switched networks can’t also provide phone lines to meet the ISDN specification. It’s all a matter of hardware and firmware on circuit cards to get the signals formated properly.

Comcast, the largest cable operator in the US, is now offering PRI telephone trunking over their Hybrid Fiber Cable (HFC) system. If you are only familiar with Comcast as a provider of Cable TV service or broadband, you may be surprised to learn that Comcast is the third largest telephone company in the country. The other possible surprise is that Comcast is a business as well as residential service provider.

Coaxial cable has bandwidth capabilities far beyond those of twisted pair copper telephone wiring. This is especially true when most of the network is built on fiber optic cabling and only the last mile or less uses coax. Coax is cheap, reliable and well-proven technology. There is plenty of room on that coax to delivery television, broadband and telephone services, including ISDN PRI.

But isn’t broadband telephone fraught with performance issues? The Internet often isn’t up to traditional telephone standards when it comes to voice distortion and latency, the annoying time delay that makes you pause during two-way conversations. That’s why Comcast keeps their broadband and telephone signals separate. They’re both riding the same cable, but in different channels so they don’t interfere. TV signals are also on the same cable in their own assigned channels.

What makes PRI over Cable a great option for a small to medium size business? Consider that you can get a 6 channel telephone trunk capable of serving up to 24 employees plus 22/5 Mbps broadband Internet service for less than the cost of many T1 lines. Most companies need both telephone and Internet service, and Comcast’s business class Business Class Trunks and Internet with broadband speed up to 22 Mbps download easily fits the need.

Do you need a larger phone system capacity or are concerned that you will in the future? No problem. Comcast lets you add to your PRI service in single channel increments. Many ISDN PRI services now come with a full 23 lines even if you don’t need that many. Having a system that is scalable for both phone lines and Internet bandwidth gives you the ability to buy just what you need now and be able to easily upgrade in the future.

Could you benefit from the flexibility of business telephone service that will grow with your business or just want to see if you can save on ISDN PRI over Cable with or without bundled broadband service? If so, get pricing and installation times for ISDN PRI and bundled services for Comcast Business Class. There are also attractive voice and data plans from competitive carriers where cable services are not available.

USA Digital Offers Comprehensive Call Center Services

Call centers and company contact centers have special requirements for the high volume telephony services they use. USA Digital serves this market with a suite of high performance cost effective telecom services.

USA Digital Communications Inc., often called USA Digital for short, is a licensed, certified carrier in all 50 states. Since founding in 1991, their business has been known for rapid growth and customer retention. Wouldn’t a lot of companies like to claim that? The secret to USA Digital’s success may be summed up as excellent customer service combined with an extensive range of services to support both voice and data needs.

Call center operations are a special focus for USA Digital. It starts with digital line services from T1 through OC12. T1 is a popular service and provided by many carriers. However, not all of those T1 services are optimized for cost on high volume calling. For instance, USA Digital offers initial six second billing minimum. That’s typical in the industry. But then USA Digital billing switches to one second increments. That alone can save you 30% in the cost of the minutes you use.

Another big saver is 4 digit versus 2 digit rounding. Those decimal points might seem arcane, but in high volume calling minor fractions of a second add up to big money. That’s especially true if 4 digital rounding is combined with low dedicated interstate rates on T1 service.

USA Digital has a service team experienced in provisioning voice lines, PRI’s, CO meet-point circuits, cross connects and SS7 links. That same experience is applied as you move up the circuit class to DS3 (T3) trunks and into the fiber optic services from OC3 to OC12. These OCx connections are truly business carrier class services needed by the largest call center operations and requiring the highest levels of expertise for support. An OC3 gives you the capacity of about 3 DS3’s and OC12 is the bandwidth of 4 OC3’s or 12 DS3’s. USA Digital can deliver OC3s in the form of 3 DS3’s that may be separated into individual T1 services.

In addition to bandwidth, dedicated outbound services are a specialty of USA Digital. They offer FTC telemarketing sale rule and do not call services to make sure you are in compliance with government regulations for outbound call centers. Their do not call services are capable of blocking 100% of calls registered to both state and national do-not-call lists. In addition, USA Digital provides customized Caller ID Service so that you can communicate appropriate caller information over your service lines.

USA Digital’s services are appropriate for in-house customer service contact centers up through major independent call centers and carriers, including ILEC, CLEC and wireless. Beyond traditional switched circuit voice trunks, they also support VoIP (SIP, H3223), point to point dedicated lines, and MPLS networks for linking multiple business locations.

Can you benefit from business telecom services like these? If so, you’ll want to get customized telecom service pricing and consultation for USA Digital and other competitive service providers as soon as possible. You could be looking a major cost savings.

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.