Conferencing suddenly stopped working site-wide (internal and external)

[handwritten]

A few weeks ago, conferencing stopped working for all users on 5312/5212 and 5304 sets.  Interestingly, it still works for users on 5340 sets. 

When Alice presses the trans/conf button while on a call with Bob, she is able to dial Carol and talk to her.  But when she presses the button again, there is no incoming/outgoing audio, even though the screen shows 3 PARTY CONF.

The 3300 has been rebooted since this started, and that has no effect.

I made sure that the System Options fields were set correctly:

Code: [Select]

Maximum CO Trunks In A Conference 3
Maximum Parties In A Conference 5
Maximum Trunks In A Conference 4
Any thoughts?

[lundah]

Do you see anything in the maintenance logs when someone attempts to set up a conference? Sounds like a hardware problem but hopefully there's a log message generated to help point you in the right direction.

[handwritten]

Thanks Lundah.  There's nothing conclusive in the logs, but our vendor suspects it's a problem with the echo canceller card.  We'll swap it out and see if that fixes it.  I'll report back.

[Mattmayn]

Most likely the DSP not the echo canceller.