I installed lately Mitel SX200 Digital, the PBX contains 20 trunks and around 300 analog lines and 1 console.
The problem i'm facing is as follows:
Sometimes when a outside line is transfered from the console to an analog extension, the line disconnect when the extension answers.
In addition, sometimes when an extension call another extension the call disconnect, and the other party hears nothing "silence" he should goes ON hook then OFF hook to get the a dial tone again.

This problem happens rarely, and it's not a cable or installation problem, it's 100% from the PBX.
I tried to change the Station line card with another one, the problem disappeared but the weird thing is that when i re-installed the station card with the mentioned problem in a different slot the problem didn't re-appear.

I was wondering if you can help me solving this problem or even troubleshooting it.

Mark

I'm not an expert here---but the on the Mitels that I service--the first thing I do when something "goofy" is happening is to reset the offending card, switch them to another sloe( like you did) or to reset the system. From Mitel techs that I know---the system just "loves to be reset" at times. Good luck

Sounds like you need a few more DTMF receivers. That would fix the no dial tone issue. The disconnect problem would normally be a ring trip(bad relay) for the port. Are you using ONS digital cards or old style 9110-110 analog cards. If you are using 9110-110 I would get some spares handy.