A customer is asking for recommendations in replacing their WAN equipment w/ Cisco gear. One of them is a Qwest T1 circuit currently terminating on an Adtran 3430 router. Our initial information led me to believe that this was a data-only T1, so I was preparing to scope a 1921 ISR w/ a T1 card in it (or even a lower end SR-520 router), either of which could've handled a single data T1 w/o a problem.
I've now been told that this T1 is actually being used as "a flexpipe for voice and data", which tells me that it's also providing PSTN access to the location in addition to Internet. I've not as familiar w/ these types of setups, so I'm looking for help in how to build a router to handle this connection and replace the Adtran, which specific module(s) I might need, or what types of questions I should be asking before this can be determined.