Conference calls are dropping.

[mvourlias]

Hello.

I am running Call Manager 3.1.2. with an array of 7940 and 7960 phones. Users cannot place conference calls without them dropping. Internal or external conference calls last between 5 and 30 seconds then are dropped. Phones display 'Temporary failure'. Please assist as I am a newbie to the Cisco IP phone system.

[thomas.chen]

Do the phones share a common piece of hardware? Could be a bad blade someplace. It could also be a reincarnation of CSCdr41623.