[Asterisk-doc] Connecting to a PRI

[Nick Bachmann]

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