I have just setup an Adtran 924 with a Telco PRI for DID calls, and FXS ports going to a 911 center's Intrado system for non emergency admin calls. Inbound and outbound calls work fine.
It is when the 911 operators want to transfer an inbound call from their consoles back out the Adtran using the PRI, that the audio is not working between the original PSTN caller and the PSTN party the call was transferred to.
The original calling party and the person receiving the transferred call from the 911 center show connected, but hear silence until one party drops the call. The 911 operator no longer sees an active call on their consoles one the transfer is done.
Any ideas as to what is causing this issue?
