RMX 4000 (sw 8.2) with ISDN card connect via E1 to Alcatel S-12.
We use isdn for connect audio parcipant to conference.
Sometimes have problem - no audio from parcipant to server and rmx not detect DTMF.
Audio from rmx to parcipant is ok.
ip parcipant communacation no have problem.
In rmx and S-12 no warning
only reboot rmx fix problem.
When your audio participant connects and the issue occurs, have you looked at the Participant Properties to see the audio protocol being used? Is it ALL audio calls coming in that experience the issue or consistently certain ones (from a certain network possibly)?