Repeater remote control from a radio


Dynamic Mixed Mode provides a convenient means of providing repeater coverage for both analogue and digital radio users. However there are some situations where IP Site Connect and analogue service many be desired. Dynamic Mixed Mode does not support IP Site Connect, but there's another means to provide local repeater coverage, in analogue, when needed.

This configuration would allow an analogue radio user to bring the repeater out of digital mode by means of Select-5 signaling.

What you need.

For this, the following equipment would be needed:
  • DM4400 (or DM4400e) mobile radio
  • SLR5500 repeater with duplexer; antenna etc. (other MOTOTRBO repeaters will work too)
  • Separate antenna for the DM4400 - or multicoupler to distribute received signal from the repeater antenna

In addition to the above, you will need a custom built cable, consisting of shielded multi-core cable (gauge is not important but 1mm² stranded should be fine); a D-sub DB25 male plug and a Motorola PMLN5072A accessory connector kit. The custom cable would need to wired up as follows:


The DM4400 would need to have the following configured (click to enlarge any of these pictures):


There needs to be a third channel added to the repeater. If Pin 4 and 5 are low then the repeater will go to channel 1. If Pin 5 goes high, the repeater will switch to Channel 3!

The SLR5500 will need to have the following configured (see above):
The user(s) who has (have) the ability to switch between analogue and digital will need to be able to send the following Select-5 telegrams:

  • 080001 (switch to digital)
  • 080002 (switch to analogue)

These would need to be sent on the receive frequency of the DM4400 in analogue mode.

How it works.

Sending 080001 from another radio causes pin 17 on the DM4400e accessory connector to go high (assert). This changes the state of pin 5 of the SLR5500 accessory connector to high which in turn causes the repeater to select Channel 2.

Channel 2 is selected becuase pin 4 - Channel Select 1 - is tied to ground. Channel Select 1 and Channel Select 2 form the BCD number of the channel - so 01 and 00. Since there is no channel zero, the repeater reverts to channel 1.

Pin 18 on the DM4400e and pin 4 on the SLR5500 are the common ground.

Sending 080002 from another radio will cause pin 17 to go low (de-assert) again.
In this state the DM4400 should not (must not) transmit.
By default, ZVEI 40ms is used.


The repeater could be controlled from a digital channel using telemetry - in fact more channels could be controlled this way!
An acknowledgement could be sent from the DM4400e to confirm that the request has been received. In this case, you need to make sure the DM4400e has its own antenna (that it can transmit on).

I am assuming that RDAC cannot be used but if it can, this makes more sense.

Please see Errata above.

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