Misalignment of the Mediatrix on Primaries and BIS
This problem occurs when the Mediatrix connected to the primary flow or to ISDN lines, while showing Up on the Physical link and Signaling states, displays one (the first) or two channels in Idle, on which it is sometimes possible to make / receive calls, but all others appear in the Maintenance state and are therefore unusable.
Usually restarting the Mediatrix or resetting the rotuer (or flow) does not solve the problem..
It is likely that the control unit or the apparatus that provides the primary flow does not recognize all the Q.931 signals. This can happen both when interfacing with flows emulated by gateways and routers (eg Patton) or even with flows that arrive directly from the operator’s control unit.
In these cases, you can try to disable the Send Restart on Startup parameter (accessible from the ISDN menu – Primary Rate Interface or Basic Rate Interface), setting it to Disable. In this way the Mediatrix will no longer send (as expected by default) a Restart command of the channels as soon as the channels go up.