sundance-communications.com/forum Forums Wiring - Telecom Carriers - Trunks & Services T1's, CSU's and DSU's PRI Channels

I understand (or I think I understand) that a PRI carries 23 B channels and 1 data channel. If that's not correct, someone please correct me.

With that in place, do each of those 23 B channels carry one phone call respectively meaning that a PRI can have 23 concurrent calls traveling through it?

I'm a little foggy on this topic. I would appreciate any advise.

sounds right to me!

23 B channels would be the maximum. In theory....you can have fewer than that....in situations where voice & data share the same T1 pipe.

You can think of a PRI just like a standard T1 in terms of the individual channels being able to simultaneously carry either 24 (T-1) or 23 (PRI) conversations. The BIG difference between the PRI and T1, other than the obvious one talk channel less with the PRI is that you can have caller ID with a PRI. Caller ID is possible, but highly improbable, on T1 circuits. I think MCI was the only carrier that offered caller ID on T1. At least, that was the situation here in PA.

Rcaman

With the proliferation of VoIP, these days you can have a full 24 channel T1 that functions as a PRI. But with standard TDM based voice, a PRI is 23 channels- as everyone else has already mentioned. And yes it can handle 23 concurrent calls.

As far as caller ID goes, a regular voice T1 can transmit caller ID as well (based on my experience). It's just that with PRI it tends to be more reliable. And in some cases if you want caller ID number + name transmission you might need a Local PRI, rather than just LD (Long Distance). But this isn't always necessary as I've seen plain LD T1s transmit both caller ID number + name. It all depends on where the call is being terminated.

IMO- I think the main advantage with PRI is that is sets up and breaks down calls faster. Which is an advantage for predictive dialer systems used by outbound call centers. For inbound call centers, PRI can help make use of specialized routing such as DNIS/screen pops (probably more info than you wanted to know;-))

Great! Thanks everyone for sharing your knowledge. Each of you has been most helpful.