Modem Passthrough on 3660?

christopher.l.lawson · ‎12-12-2001

I'm trying to connect analog modems to FXS ports on a 3600 which routes the call out a T1. I can only get 22k connections and even those are pretty shaky. Faxes work fine going through the FXS ports.

Does the 3660 support modem pass-through? What do I need to do to enable this? Right now, the 3600 is serving as an H323 gateway to CM 3.0.

We also have a VG-248 on order. Will that support analog modems?

paul.harrison · ‎12-13-2001

NOOOOOOOOO!

Do NOT do it.

There are BIG BIG problems trying to do hairpinning on the same box. I went through massive headaches about 4 months ago trying to get fax calls coming in on an E1 on a cat4K AGm to terminate on an FXS port on the same blade, in the end Cisco TAC loaned me an AS5300 (talk about sledge hammer to crack a nut but I ain't complaining) and that fixed the problem.

If you have FXS ports on a seperate box then use them (the VG-248). It seems the boxes can cope with jitter over IP and compensate accordingly, but not over their own back planes.

Paul