MMDVMHost timers

The new CallHang parameter controls the DMR talkgroup hang time. This is the amount of time after the end of a transmission that is reserved for replies using the current talkgroup.

A radio that is correctly set for polite access (colour code free) will be able to transmit during this period if it is using the same talkgroup. A radio set to a different talkgroup will receive a channel busy message. The hang time is timeslot specific. The two timeslots are handled separately so one can be in CallHang time while the other is in use or idle.

This is a standard feature of commercial DMR repeaters that was not previously implemented on MMDVM. It helps prevent a call in progress on one talkgroup being interrupted by a user trying to use a different talkgroup. Some Chinese radios have had (and may still have) a bug in their firmware which doesn't handle the hang time correctly. These radios will not allow a radio to transmit even if it is using the same talkgroup. That's the main reason many people ended up setting their CS700s and MD380s to impolite access. For the same reason people also complained that they couldn't transmit until the repeater had dropped carrier. Motorolas and Hyteras have always handled the hang time correctly. I believe the latest CS700 and CS750 firmware also now works correctly. Not certain about the MD380. I will have to test it.

At the end of the CallHang period the repeater then changes to the idle state for the duration of the TxHang parameter. During this period any radio is allowed to transmit. When the TxHang period expires the repeater turns off its transmitter.

The ModeHang parameter then controls how long the repeater remains locked onto the current mode. (DMR / Dstar / YSF) . After the ModeHang period has expired the repeater will accept any mode.

Colin G4EML

It makes no sense to have the DMR transmitter on when the repeater is not in DMR mode. Therefore the DMR transmitter hang time must be the same or less than the ModeHang time.

Jonathan G4KLX