What is the difference between a T1 & PRI?

I’ve read about 15 different blogs & websites, and no one seems to agree on a clear cut definition of the difference between what a T1 & PRI is!

My understanding (and what I believe is correct) is that the T1 is the actual HARDWARE that provides the interface for connectivity to the ISDN. The SERVICE that runs over the T1 is called either a PRI or BRI. The BRI has basically 3 dedicated lines, whereas the PRI has up to 24 channels.

Am I missing something? Is there another way or service that allows the T1 to communicate with the telco provider?

I’ve read so many different websites that have referred to the T1 as the actual SERVICE and the PRI as an entirely different SERVICE that all it has managed to do is thoroughly confuse me! :neutral_face:

well this should become an interesting thread since there is a lot of ambiguity in the definitions and common use/misuse of the assorted terms. I typically understand the terms as follows: T1 (or DS1) is a telephone world term for a 1.544 Mb data pipe. It can be divided into 24 56kb channels [the typical method when using a T1 for a data connection as your internet pipe] or as PRI which channelizes the 1.54 Mb into 23 voice channels + 1 data channel.

For more than you ever wanted to know: dcbnet.com/notes/9611t1.html

there is a wikipedia somewhere en.wikipedia.org/wiki/Primary_Rate_Interface
T1 PRI = 23B+1D channels
E1 PRI = 30B+1D channels
BRI = 2B+1D channels