A site starts the equipments, and the self-loop test no problem, but this site can’t join into the meeting.
The MUX board self-loop didn’t contain the interface module. So we can do the circuitry test of MUX board (using the self-loop cable to do the hardware physical self-loop). After the test, found out the MUX board has fault. Test the interface module, found out a chip in interface module burnout.
When the grounding of the system malfunction, the interface module of the MUX board is easy been burnout. If the interface module burnout, the terminal can’t join into the meeting.