Voice T1 service is frequently very expensive since you are still paying almost as much per month for the 24 lines PLUS the cost for the T1 being used to transport them to your premises.

PRI is much more economical since all channels are dynamic, in that they act in many different ways depending upon the call type being made or arriving. The rate structure for them is also much different for a PRI, meaning that there is less "head end" cost. A PRI requires less hardware on the telco end, so there is less cost for them. This, in turn is passed on to the customer.

ISDN-PRI really is the only way to address your needs, as long as your system has the capability to interact with the power of an ISDN circuit.

Ed Vaughn, MBSWWYPBX