How many channels are in a full T1 PRI trunk?

How many channels are in a full T1 PRI trunk?

• 23
• 6
• 24
• 32 

 

 

EXPLANATION

T1 connections have 24 channels in total.

Typically, for T1 ISDN (CCS) protocols, 23 channels are used as B-channels and 1 channel is used as a D-channel. For this reason, the frame structure of a T1 PRI connection is said to be 23B+1D where the D-channel is located on timeslot 23 (channels numbered from 0 to 23) and the remaining channels are used as B-channels. Hence;
If you had an E1 PRI trunk, you would have 30 B channels and 2 D channels.

SOURCE

https://en.wikipedia.org/wiki/Primary_Rate_Interface