Gene Naden wrote:
Here is my explanation of the issues involved in connecting to a PRI. I am
open to feedback, corrections, comments. This is a text file with line
breaks.
Gene Naden, MA
Programmer Analyst
GlobalTeldata II, LLC
4700 N. Ravenswood
Chicago, IL 60640
(773) 878-3161 x 223
------------------------------------------------------------------------
WHAT IS A PRI?
A PRI is a 24-channel connection to a telephone network such as the Public
Switched Telephone Network (PSTN). PRI is a type of ISDN (Integrated
Services Digital Network) connection. A PRI can carry 23 voice channels.
The 24-th channel is used for signalling. The voice channels are referred
to as B channels and the signalling channel is referred to as the D channel.
Because a PRI uses a four-wire local loop, d4 or esf framing, and AMI or B8ZS
coding, it may also be referred to at T-1. However, T-1 can be used to carry
either voice or digital data.
As other people have pointed out, T1s are North American. The generic
term DS1 is probably best here--a DS1 can be an E1, T1, J1, etc.
Basically any type of DS1 circuit can be provisioned PRI. Also, the
underlying circuit _IS_ a T1 (or whichever); the distinction between
types of T1s is in the provisioning and protocols used on the line.
Finally, a T1 circuit can also cary be provisioned to carry both voice
and data and the same time.
Nick
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