Looking at INE topology for the ccie voice lab setup, I see that they used 3725 as a PSTN and Frame-Relay switch. I also see on their site the following

modules they used in 3725 router

(Qty 2) VWIC-2MFT-T1

(Qty 1) VWIC-2MFT-E1

(Qty 1) NM-HDV

(Qty 2) PVDM-12

Also looking at the specification of 3725 router it has the following

3 VWIC/WIC (data only)

Comparing the modules used by INE and the specification of 3725 router, does this support both PSTN and FRAME-RELAY capabilities? I ask because the

single NM-HDV will be combined with one VWIC-2MFT-E1 or T1, but how about the remaining two VWIC-2MFT E1 or T1 if INE only used a single NM-HDV?

Because the built in slots on the 3725 router supports the VWIC-2MFT-x1 but in DATA mode only, meaning FRAME-RELAY support only and not PSTN (voice).

Base on my understanding on the modules and 3725 router, to support both PSTN and Frame-Relay it should have this modules

(Qty 2) VWIC-2MFT-T1

(Qty 1) VWIC-2MFT-E1

(Qty 2) NM-HDV         --> One for VWIC-2MFT-T1 and one for VWIC-2MFT-E1

(Qty 6) PVDM-12        --> Four for one NM-HDV and two for the other NM-HDV

Please correct me if I'm wrong and if INE modules for PSTN/Frame-Relay is sufficient