[c-nsp] SIP to T1

[Anton Kapela]

> We have an application where we would like to take 2 "PRI SIP Trunks"
> from a softswitch into a Cisco 2621 from an Internet 
> connection and then output two T1's to a PBX switch that has 
> T1 ports... 

It sounds like someone is going to be sending you trunked calls signaled
via SIP over the big-I internet, and you would like to convert this to
some form of ISDN signaling on a t1 interface so that you can connect
your PBX or KTS; correct?

> can this be done?

Yup.

> Unfortunately the PBX system doesn't understand IP...
> 
> I understand the Cisco 2431 IAD can do this as well but since 
> we have lots of 2621's kicking around would like to try using 
> them up...

Drop in a NM-HDV, add a VWIC-1MFT-T1 and enough voice DSP cards to
support the number of channels & codec's you require, and you should be
set. If you can somehow find a 2651xm (or any of the xm's really), you
could go the route of using a VWIC-1MFT-T1 tied to a AIM-VOICE-30 (via
'network-clock participate' on whatever wic slot the vwic is inserted). 

This only works on XM's as the 26xx standards don't have the right
connections from the wic slot(s) to the AIM slot, given the need to
synchronously couple the vwic t1 port to the dsp's on the AIM. 37xx's
also support AIMs, but that's a lot of box to 'waste' on doing a few pri
worth of sip trunking on. 

Also, with the AIM solution you cannot grow to support more than a
single T1 tied to the aim slot, whereas with the NM-HDV, you could in
theory insert a two port t1 vwic; however, this is where it tops out as
well. For anything denser, try AS5350 or 5350XM.

-Tk