Problem with Cisco CUCM working behind SL100 using ISDN.

[daleshew517]

Hello.  I work at a University that is basically using two phone systems.  Our campus departments use Meridian phones off of our SL100 and our hospital departments use the Cisco Call Manager.  The two systems are linked together using PRIs, DTCI cards, and Cisco gateways.  We have come across an intermittent problem where when a Cisco phone calls a Meridian and the Meridian hangs up first, the Cisco set will stay off hook until the user manually hangs up.  This doesn't happen on every call and does not happen when the two types of sets call each other.  Has anyone else who might be using a similar setup ever experienced this problem?

Thanks.

Dale   

[Manish Gogna]

Hi Dale,

To troubleshoot this issue you will need to provide the following info to begin with:

CUCM version

Phone model and firmware involved

If the issue is intermittent then get the callmanager service traces for a good and a bad call so that the signaling can be compared for both.

Manish

[Jonathan Schulenberg]

Before even bothering with CUCM or Cisco phone firmware you should look at the PRI: does the SL100 cleanly tear down the call? 

You can see this on the IOS gateway with debug isdn q931. Does the SL100 send a DISCONNECT for the call when it happens? My guess is that it doesn't or there is something very abnormal if if does. Start there before fooling with CUCM