Silent Calls when Transffered to SIP Trunks

[marcrp]

Hi,

We have some SIP trunks that are connected to a 3COM switch.

They work fine when calling the extension directly (ACD extensions).

However in the last couple of days we have got an issue where if someone on our site is transffered to an extension on the end of the SIP trunks it is silent. However if they are transffered but the person doing the transfer waits until the ACD automated message kicks in and then hangs up to complete the transfer the call is OK.

I'm struggling to think what it can be?

Any help appreciated.

[brantn]

Check QSIG Diversion, Public Network to Public Network, and a killer one ISDN Progress

Last two are class of service options on the trunks. First one is a system option.