[Serusers] SIP call to ISDN subscriber

Hi all, I have a problem calling from a sipset to a ISDN subscriber over a CISCO 1760 GW. The following setup is used. UA ---> GW ---> ISDN The UA is a sipset, the GW is the CISCO 1760 with ISDN BRI interface and a standard ISDN subscriber. The UA is registered with the SER server. All numeric userparts of the SIP URI are rewritten and routed to the GW. The GW's BRI interface is connected to the PSTN. The call signaling seems to work as the SIP phone indicates ringing and the ISDN phone is ringing. After picking up the hook of the ISDN phone the UA shows "In Call". But after a second the call is terminated. The log shows that the GW sends to both side the call termination messages. TX -> DISCONNECT "Normal Call Clearing" to the ISDN side and a BYE message to the SIP side. The signaling in short: UA GW ISDN INVITE -> | <- 100 Try | TX -> SETUP | RX <- CALL_PROC | RX <- ALERTING <- 183 Sess | | RX <- CONNECT | TX -> CONNECT_ACK <- 200 OK | Milliseconds later ! | TX -> DISCONNECT | RX <- RELEASE | TX -> RELEASE_COMP <- BYE | 200 OK -> | Any hints how to solve this problem. Thanks Manuel -- +KOM----------------------------------------------------------------+ |Manuel Görtz Merckstrasse 25| |Darmstadt University of Technology 64283 Darmstadt, Germany| |Multimedia Communications Tel: (+49) 6151 16-5175| |Multimedia Networking & Distribution Fax: (+49) 6151 16-6152| +----------------------------------------------------------------KOM+