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PRI - Prime Rate Circuit

23 simultaneous conversations - channels
No individual Phone Lines, reduced monthly telecom fees


  • A PRI (Primary Rate Interface) line is a form of ISDN (Integrated Services Digital Network) line which is a telecommunication standard that enables traditional phone lines to carry voice, data and video traffic, among others.
  • A PRI circuit consists of two pairs of copper lines terminating on a modem from a service provider premises to the customer premises. It uses multiplexing/de-multiplexing techniques to carry more than one channel in a single circuit. There are two common forms of PRI lines – E1 (which carry 30 channels in the two pairs of copper lines, common in Europe, India) and T1 (which carry 23/24 channels in the two pairs of copper lines, common in United States).
  • Each channel in a PRI line provides 64 Kbps for data transmission.
  • A PRI line can connect to both Analog/Mixed EPABX systems and also the newer IP PBX systems. A PRI Card / Interface might be required to terminate the PRI circuit on the PBX.
  • A PRI line can also be used to connect two PBX systems thereby providing 30 channels between them for interoperability.

DO you have mltiple locations?   Do you have multiple phone systems?  Imagine if they were combined into a single system, and you could direct dial each location? How about conferencing multiple offices and locations?  There are a number of advanced possibilities. The most important is the reduced cost!!! Why is this cost lower? because the switching of PRI allows acore line to use 23 channels for calls. 

If you think about your traditional systems, one line, one call If you have seven lines, automatic switch-over to find an open line is not possible. You manually select each line or look at the lights on a multiple line phone and see an open line. In a PRI environment it does not matter, pick up the phone and it will automatically find an open line. Same is true with incoming calls. NO NEED TO WORRY ABOUT THE BUSY SIGNAL.

Your bill becomes a single charge per month. With PRI there  is a base rate,  You can budget based on this.  No need to worry about phone number assignments. You own the numbers. How many times have you found phone number charges on your bill and you have no idea wherer the phone is located?  

Why pay individual Telecom fees for each and every-line,  for instance service fees, directory listing, etc. Look at your standard phone bill for each line you have What are all those extra charges?  This is not true with a PRI service.

Case Study

City of Easton

Five Phone Systems throught the City
Verizon phone service - 128 individual phone numbers
Annual Bill $82,000 per year

Implemented digital IP based phones with PRI service
Average  $36,000 per year
Removed all phone systems and aggragated into a single system located in the IT department City Hall

f.p.caruso&associates