Call drop every 5 minutes

[f.huynh]

Here is my problem:

[pstn] --- [Inter-tel PBX] ---E1----(VG 200)-----VPN------Callmanager/another GW

VG200

interface Serial1/0:15

isdn switch-type primary-net5

isdn protocol-emulate network

isdn incoming-voice voice

isdn T310 60000

Every time when I call from the callmanager or gateway, i have test with and without CCM, my call got disconnect at exactly every 5 mins/300sec. The disconnect cause is just a normal call clear. The Inter-tel PBX is an IP pbx, but it can only interoperate to cisco throught an E1/T1 connection since it doesn't support h323. Is there any timer in the gateway that i can configure to prevent this from happen?

[thusain]

Are you getting answer supervision back from the PBX. Do a show call active voice brief when the clal is active and you should see both legs in active state rather than connecting state. You can not configure or force answer supervision, however if it is e&m signalling you can configure auto cut through under the voice port so it does not wait for answer supervision.

[f.huynh]

After talking with TAC, the problem is solved. It turns out that there are nothing wrong between the PBX and gateway. It turns out there is a bug in the pix firewall where the rtp stream got disconnect after 5 minutes because the pix didn't detect any tcp message. After removing "no fixup protocol h323", the call stay on until I hang up.