It’s TIME to TALK DIGITAL!

What is ISDN PRI? And how does it compare with POTs and VoIP service

PRI stands for: Primary Rate Interface

PRI is an ISDN equivalent of a T-1 Circuit. ISDN delivers local service, long distance service, DID (Direct Inward Dial) and Internet Service over one 4-wire interface. The ISDN PRI has 23 channels that carry voice and data. Each channel has 64k of bandwidth. The 24th channel is called the D channel or Data Channel. The D channel communicates continuously with the Central Office ensuring proper data is transmitted and there is uninterrupted transmission of data to and from the PBX or phone system. The data from this channel can be used for routing calls based upon incoming pre-arranged routing information.

Most business users currently use POTs lines to deliver tier LOCAL SERVICE. POTS lines or Plain Old Telephone service Lines are pretty much the standard method of delivering analog dial-tone voice lines to a small to medium business user. They are sometimes referred to as CO+ lines or 1FB lines. POTs lines are used for such things as making and receiving local calls, long distance calls, faxing, modems, security systems and credit card/ATM machines.

For each POTs line there is a separate port on the phone system to plug each line in on. There are Line Cards in a phone system to plug them into and there needs to be enough capacity in the phone system to support enough line cards for the demand. The costs for POTs lines vary dramatically from region to region. POTs lines carry monthly fees; taxes etc. and these charges are associated with each line individually. The problem is that the cost for POTs lines can be high. In some areas as high is $50.00 per line plus as much as $8.00 to $10.00 in additional fees then taxes added onto the total.

There is a standard rule of thumb that if a company is using 10 POTs lines it will be at pretty much break-even to the cost of bringing a PRI in to replace them. Anything over 10 and it will likely be saving money with a PRI. Although these numbers can vary by region, by provider, etc.

With the advent of Voice over IP, ISDN PRI is rapidly becoming obsolete. With the various SIP or Session Initiation Protocol (SIP is required to make it possible to send calls over the internet) and other Internet Protocol trunking products available today, the same service can be provided to customers over an existing Internet circuit at substantially less than PRI’s cost today and instead of having to give up a channel to support data, they can be provided with 24 complete voice paths instead of only 23. In addition, many companies are in need of only 10-15 lines, and PRI will save them money, but the PRI comes in only one flavor, 23 lines + a D channel. There is no break for needing less than 23 lines. With VoIP you can deliver the same functionality for only as many lines as they need.

Example:

POTs Cost:

16 POTs Lines @ $40.00 each plus Fee’s of 4.95 each: Monthly costs less taxes: $719.20

PRI cost:

A typical charge for a PRI is between 450.00 and 600.00 per month with usually fees of around $50.00. So a customer can get 23 lines for and average cost per line of $23.00 to $28.26. Or a monthly cost of $500 to $650.00 per PRI. Of course the D-channel is included in those numbers. The customer will require a PRI card to be able to plug the PRI into the phone system. This will cost several hundred dollars plus install fees. It is generally paid for very quickly by the savings of going from POTs to PRI. In this example, savings is between $200 and $70.00 per month.

VOIP Cost:

With VoiceWalker’s Line/Trunk Replacement product, we can bring in 23 “Voice Channels, on an existing Cable or DSL service for Internet for as little at $15.00 for a full 24 lines or $360.00 per month. This is a monthly savings of between $90.00 and $240.00 verses the PRI. There is no loss of features at all by making this change.

When compared with the POTs lines, we can bring in just 16 Voice Channels, at $15.00 each or $240.00 monthly for savings in this example of $479.20! Since they really only needed 16 lines, there’s no need to force them to use, and pay for 23 lines.