[c-nsp] SIP to T1

Ueli Heuer papierkuebel at gmail.com
Wed Nov 15 15:29:51 EST 2006


On 11/13/06, Anton Kapela <tk at 5ninesdata.com> wrote:
>
>
>
> > 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.


We have a smiler setup (PBX [E1] --- C2811 -- [E1] PRI and a
SIP-Account on the 2811. (it is planed to remove the E1 PRI later).
The signaling from external  calls to the PBX worked fine.
But we are stuck in the other direction (PBX -> SIP or PBX -> PRI
trough the 2811). the PBX sends the digits as you type the cisco used
only a few digits (too few) and setup the call with a too short
number. of course these calls are failing :(

does anyone have a hint to solve the 'dialout' trouble?

Regards,
 Ueli


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