On the terminal, the image and audio of the code/decode local loopback and multiplexing board local loop back are OK, but can not enter conference as other terminals, the near/far end are all out of sync when we test MCU.
The video conference system is test as follow:
1,Comference site 1:
a) The terminal operation bench can communicate with the host but can not enter the conference, the image and audio of the code/decode local loopback and multiplexing board local loop back are OK, so the terminal is OK.
b) In the MCU’s operation system, set this conference site in conference at anytime, and we will see the green icon.
c) In conference control panel we can see the LSD and HSD have a cross.
d) Tested the conference sites and found the near/far end of this terminal was all out of sync.
e) From step b, c, d, we know the far end of the terminal can not enter, examined the connection cable terminal’s back board and found one of the 2M joint was not inserted, so we connected it and tested again as the step b, c, d, they are all OK, the terminal can enter conference and the near/far end are sync, this has showed us the fault is induced by transmission.
2,Comference site 2:
Examined transmission line, the E1 line of this site is connected to the DDF distribution frame in local call transmission equipment room, we connected the G network and do the local loopback, the near/far end was out of sync in the MCU test. We examined the line and found the fault, then we replace the relay joint, the site can enter the conference.
3,Comference site 3:
A E1 joint that connect to MCU break down, after replacing it, do the local loopback with no continuity. We check the connection found 2 BNC joint were badly connected to the DDF distribution frame, after replacing it, the site could enter the conference.
The interruption of transmission line make the terminal can not enter conference.