The 3 Types of VoIP Lines for Business

By: John Shepler

Businesses large and small have been migrating to VoIP telephone technology for years now. Some are delighted with the move and have never look back. Others feel like they’ve lost something in the way of performance. The calls are often muddled and it’s hard to carry on a two way conversation. Would you believe that its the exact same technology involved? Why is it that VoIP telephony can range from excellent to unacceptable? Let’s take a look.

What’s VoIP
VoIP or Voice over Internet Protocol is a means to convert telephones into computer peripherals. The reason to do that is both to save money and enable applications that just won’t work on the old style telephone network. Network voice is a powerful tool, but can more easily be degraded that simpler analog phones.

Old School Phone Systems
Business phone lines are sometimes called POTS for Plain Old Telephone Service. They consist of twisted copper pair wires that run directly from the phone set all the way to the telephone company. Each phone has its own set of wires. Once you get more than a few phones, however, you face a mounting phone bill since the telco charges you to make internal as well as external calls.

Companies get around this by installing their own phone switches. Small systems use Key Telephone Systems where multiple outside lines are available on each phone but you can also call within the building on your own wiring. Larger companies install PBX (Private Branch Exchange) switches that manage a pool of outside lines that can be assigned to any phone as needed.

If you only have a couple of phones, each with their own line, the phone company takes care of all the switching for you. With many phones, you become your own little phone company for inside calls. That means you have to take care of all the special phone wiring and the Key or PBX switching equipment. Plus, you have to pay for multiple outside analog lines or a digital PRI trunk to get to the public telephone system.

How VoIP is Different
With VoIP, each phone plugs into your company LAN. That gets rid of the second special phone network. You still need something to switch the calls between phones. This can be a VoIP PBX or IP PBX that you have in-house. It can also be a much larger hosted PBX system from a hosted VoIP service provider. Hosted means that a specialized company “hosts” or run the system. You are one of many clients that they host. It’s pretty much like buying web hosting. You simply pay by the month for service instead of having to install and maintain your own equipment.

VoIP Phone Line Needs
All VoIP phones connect to a local network. This can be a small home office network that has only a computer, WiFi router, VoIP phone adaptor (for a regular phone) and broadband modem. Or, it can be an extensive corporate LAN that is bridged into multiple business locations nationwide and even overseas. The principles and the requirements for high quality performance are the same.

Since the network is shared with many phones and other computing devices, it take some doing to make sure that you get high performance. With dedicated analog lines, that’s the phone company’s problem. With VoIP, it’s now your IT problem.

What’s needed is plenty of bandwidth to accommodate all the phones and other devices. But that’s not enough. You need to give the voice packets priority over data because phone calls will start sounding muddled and choppy long before you notice that the file is loading slower. The network also needs low latency, packet loss and jitter to be transparent to the packets carrying the VoIP digitized phone conversations.

3 Types of VoIP Phone Lines
All analog phone lines are alike. All ISDN PRI trunks are alike. VoIP phone lines can be quite different. They range from Internet VoIP to SIP Trunks to MPLS private networks.

Using the Internet as Your Phone LIne
The low end of the market, which keeps costs low for home offices and small businesses, uses a broadband Internet service to connect to the VoIP service provider. You can share your broadband connection with a couple of computers, a WiFi router, and a few VoIP phones. You’ll need a router that creates CoS (Class of Service) to prioritize the phones or the computers will interfere with your calls. Sometimes the service provider will give you an adaptor that does this.

The advantage of using the Internet as a phone line is that it’s cheap. You probably already have broadband for your computer. The lure is to save money by “eliminating the separate phone line.” The downside is that the Internet was never designed for telephony. It was intended to reliably transport data files. There is no prioritization of voice on the Internet and most access lines, like DSL, Cable, Satellite and Cellular, are shared broadband. It’s a cost vs performance tradeoff. You may find that some calls sound perfect but others break up or sound muddled. It all depends on what else is happening on the Internet while you are making your call.

One way to improve Internet VoIP is to use a dedicated Internet access (DIA) like T1 or Ethernet over Copper. This keeps your neighbors from disrupting your calls while they download large video and software programs, but you are still subject to network congestion on the Internet itself.

Private Line VoIP Service
Companies that depend on high quality phone service for customer support and employee productivity usually sidestep the Internet in favor of something more predictable. The outside line that compares most closely to the legacy analog and PRI lines is the SIP Trunk. This is a digital broadband line, but it is a private line that is not shared with others. It’s called a SIP trunk because it supports SIP or Session Initiation Protocol, the switching system for VoIP calls.

A simple SIP trunk is a T1 line that runs from your network to your service provider. It supports up to a couple dozen simultaneous phone conversations or a combination of phone calls and Internet. The Internet service has a lower priority than the phone calls and uses whatever bandwidth isn’t needed for the phones at any given time. Smaller companies that don’t have dozens of phones find this is a great cost saver compared to maintaining separate phone and broadband lines.

Larger SIP trunks are also available for bigger companies or call centers. Both copper and fiber optic bandwidth is available to support as many calls as you need.

Voice over MPLS Networks
Major corporations generally have many business sites located around the country and even in other countries. They still want any employee to easily call any other employee without paying long distance toll charges. They also need to make outside calls to anyone with a phone.

A sophisticated solution is called VoMPLS or Voice over MPLS networks. MPLS is a private network arrangement with a regional, national or international service footprint. The network operator ensures that each paying customer has the necessary Class of Service, bandwidth and low latency, packet loss and jitter that they need for high performance.

VoMPLS works a lot like VoIP using SIP Trunks. The difference is that instead of having to run dedicated private lines among all your locations, you simply need an access line from each location to the MPLS network. This can give you a major cost savings, especially on those long international connections, while maintaining high network performance.

Are you in search of a better telephone solution, to reduce costs, increase available features or both? If so, there are VoIP telephone solutions you should take a close look at.

ISDN PRI For PABX

The Private Automatic Branch Exchange, PABX, also known as the PBX, is the telephone system of choice for medium and large companies. If your company is large enough to invest in a PABX, it’s got enough employees to require multiple outside phone lines. The question is what is the best technology to supply those phone lines?

Businesses that only need a handful of telephone lines usually start off with a few analog POTS (Plain Old Telephone Service) lines and add more, one at a time, as needed. At some point you start to wonder if a digital trunk makes more sense than a dozen separate POTS lines. You are likely right.

Digital trunks are a technology to transport multiple phone calls to a subscriber using fewer wires. Each analog line requires a separate pair of wires. A trunk may use one or two pair to carry 23 or 24 phone calls.

How is this accomplished? The most popular technique is digitizing each phone call and then multiplexing all those bits onto a serial data stream. The line is synchronized at both ends so that individual time slots can be separated into channels. Each channel holds one concurrent call. This technology was standardized by Bell Labs in the T-Carrier system. The most popular of the T-Carriers is T1, although T3 is still used but generally called DS3.

The basic T1 telephone line consists of 24 identical channels of 8 bits each sampled 8,000 per second. That adds up to a line speed of approximately 1.5 Mbps. T1 lines were the first deployed as digital telephone trunks. PABX systems often have T1 interface cards and connectors so you can just plug in a T1 line and have up to 24 outside lines available. Larger systems have multiple line interfaces for 48 or more outside telephone lines.

T1 telephone is still highly popular, but is generally deployed in the form of ISDN PRI. PRI means Primary Rate Interface which uses a channelized T1 line for transport. ISDN is another standard called Integrated Services Digital Network. ISDN uses 23 of the T1 time slots for telephone lines but reserves one channel for data and switching. You give up the capability of one telephone line but gain much faster call switching plus Caller ID and ANI (Automatic Number Identification) for the other 23 phone lines.

ISDN PRI is readily available, less expensive than ever before and compatible with most PABX systems. With the capability of handling up to 23 outside lines, it has the capacity to handle the needs of most small to medium size offices and contact centers. By adding additional interfaces, a PABX system can handle 46, 69, 92 or over 100 outside telephone lines.

The competition for ISDN PRI is a newer service called SIP Trunking. SIP is the switching system used for VoIP telephone systems. A SIP Trunk is basically a packet network line with the bandwidth to handle multiple simultaneous calls and perhaps data transfers as well. Voice packets are given priority on a SIP Trunk to prevent call distortion and dropping of phone calls. A T1 line can be used as a SIP Trunk as well as for ISDN PRI, depending on how it is connected at each end.

Many PABX systems can now directly connect to SIP Trunks as well as T1 telephone lines and ISDN PRI. Some are IP PBX systems that use IP telephones as well as standard analog desk phones. What threatens all of these trunks now is not a new design of PABX but dumping the PABX completely in favor of hosted telephone services.

Hosted voice or telephone in the cloud moves the PABX from your office to a cloud service provider hundreds or thousands of miles away. You swap our your phones with IP telephones and a SIP Trunk. At the far end, the service provider does all of your in-house and outside line switching. It’s the provider who contracts for ISDN PRI trunks or other connection to the public telephone system. You simply pay per phone per month for local and long distance service plus in-house call switching. Often that is one flat fee per “seat.”

Which type of telephone system and trunking arrangement is right for your company? Get competitive quotes for POTS, T1 telephone, ISDN PRI, SIP Trunking and Hosted Voice to help with your trade study and selection.

Backhaul Upgrades For Wireless Broadband

A funny thing happened on the way to mobile broadband. We ran out of bandwidth. While everyone was thinking that wireless channels would be the limiting factor, lack of backhaul capacity is threatening to stop wireless growth in its tracks. Fortunately, this limitation is recognized and being dealt with.

Just what is backhaul and why does it stand in the way of mobile services? Backhaul, as the term is used now, means the connection from the wireless tower site back to the provider’s central office or mobile switching center.

Backhaul is something you didn’t hear much about until recently. As cellular sites were originally envisioned, they consisted of a radio transmission system with spectrum divided into multiple channels. Those channels are used to communicate with the wireless handsets to transport telephone conservations. The backhaul system consists of T1 lines that offer up to 24 individual phone lines on a digital trunk.

The beauty of T1 lines is that they are provisioned on ordinary twisted pair copper. That’s right, they use telephone line. Each T1 requires two copper pair. But instead of carrying two phone conversations, the digital line can carry 24 conversations. That’s an efficiency improvement of 12x over analog telephony. Because they use ordinary telco cabling, T1 lines can be easily provisioned to both rural and urban tower sites.

T1 lines can also be used to carry broadband Internet services. Many businesses get their broadband service over a T1 line. All cellular phone companies need do is provide a data T1 line to the tower site and use some of the available wireless channels for Internet service. That gives the user both voice and data on their mobile device.

Everything worked smoothly until newer cell phones, especially the large touch screen models, made streaming audio and video and HTLM Web browsing possible. Video chews up bandwidth like crazy. If people expect to have a television watching experience on their cell phone, the cellular transmitters are going to need bandwidth and lots of it.

This is what’s underway now. The initial response to the increase in bandwidth utilization was met by bonding multiple T1 lines to create bigger bandwidth pipes out to the tower sites. But wireless broadband speeds are increasing by leaps and bounds. AT&T’s HSPA service for 3G mobile wireless offers a max download speed of 3.6 Mbps. They are currently in an upgrade mode to double that to 7.2 Mbps. The next generation technology is 4G using LTE that will offer speeds over 10 Mbps. Sprint and Clearwire are busy building out WiMAX, another 4G technology. Verizon is running EV-DO Rev A for it’s 3G network and will implement LTE for 4G, similar to AT&T.

What this means is a big demand for backhaul service to get the voice and data signals to and from the tower sites. Carrier Ethernet can address some of this demand over multiple copper pair. WiMAX is touted as both an end-user broadband service and a backhaul technology. It just depends on where the signals go. Ultimately, fiber optic cable is the solution to the backhaul bottleneck. Fiber has nearly unlimited capacity, but it is expensive to install where there is no fiber today.

It seems like there should be some synergy between the rural broadband initiative being pushed by the Federal Government and the need for higher bandwidths to carrier-owned cellular facilities. Why not just bite the bullet and get fiber to the boonies now? It won’t be long before that massive bandwidth is going to be a necessity rather than a luxury.

In the meantime, if you have a need for voice or data bandwidth for any business application, see what bandwidth options are available for your location. You may be surprised at how much you can get at a reasonable price these days.

Why, Oh Why, PRI?

You may be familiar with the terms PRI, T1 PRI, Telephone PRI, PRI Trunk or ISDN PRI. But what do they mean and why would you select this type of service?

PRI stands for Primary Rate Interface. It's a part of the ISDN or Integrated Services Digital Network and the big brother of BRI or Basic Rate Interface. In simple terms, PRI is a digital trunk line that connects to your PBX telephone system. It combines multiple phone lines into a single digital line. More importantly, it can save you money on your monthly phone expenses.

All these terms: PRI, T1 PRI, Telephone PRI, PRI Trunk and ISDN PRI really mean the same thing. You'll most often hear of T1 PRI and ISDN PRI. The T1 part refers to a T1 line, which is a digital communications line that can carry voice, data, or video. T1 lines can be organized differently to support different applications. The ISDN PRI service is one of those. It has a very specific protocol.

PRI is organized in a format called 23 B + D. Looks a little like a math problem, doesn't it. Actually, it's just shorthand for 23 B or bearer channels and 1 D for delta or data channel. The T1 line is split into 24 equal size channels of 64 Kbps each for a total of about 1.5 Mbps total bandwidth. It's full duplex, so you get the same bandwidth in both directions.

Why carve up the line capacity into 64 Kbps chunks? That happens to be exactly the size required to transport one digitized telephone call using PCM or Pulse Code Modulation, the telephone company standard. It actually breaks down into and 8 bit digitized sample x 8,000 bits per second. The entire switched telephone network is organized around these channels, designated as DS0. They are carefully synchronized so that one call will not bleed into another.

Now, with 23 bearer channels, each "bearing" a single telephone call, you can get the equivalent of 23 separate telephone lines on one T1 PRI line. The remaining channel, the D channel, is used for call control and data. This is how the PBX system and the telephone service provider exchange information know when a call is coming in, when a line is being requested, what number is dialed, and the extent of any auxiliary information such as Caller ID.

Fortunately, you don't need to dig in any deeper than this to be able to put PRI to work in your business. You order your PRI service with so many incoming and outgoing phone lines, local and/or long distance. There a lot of customization you can do with this. Then it's a matter of plugging your T1 PRI line from the telco demarcation point (usually in a back room) into the socket on the PBX circuit card designed to accept PRI service. There can be more than one PRI interface on larger systems. Each line will deliver 23 outside phone lines.

Who uses PRI? Medium and larger size businesses, or even smaller businesses that are telephone-intensive. Sales offices, customer support, call centers of all sizes, and corporate headquarters all use PRI phone service. Why do they use it? Because it connects and disconnects telephone calls faster than the older T1 phone line service, it consolidates many analog lines into one or a few digital lines, it offers exceptional voice quality and reliability, and it's cheaper. Any business that uses 10 or more analog phone lines can potentially save money by switching to PRI service. The more lines you have, the larger the savings.

Is PRI right for your business situation? There's an easy way to find out. Use our real-time quote engine to get instant online pricing for your business location. No cost or obligation for this service.