Interfacing your controller to the Motorola MSR-2000 Repeater


The MSR-2000 Repeater is supplied with the following cards: Squelch Gate, Station Control, and Time Out (if not deleted on order).


Following these instructions, the repeater will operate with the RC-850 controller, or by the flip of a switch, with the Motorola 'cards'. This capability allows you to remove the RC-850 for maintenance without taking the repeater off the air.

Squelch Gate Card Modification

Remove the Squelch Gate Card from the cage. Install a DPDT switch (Radio Shack #275-1546) just above the 'Repeat Level' control. Then remove JU-!2 and run a wire from both jumper holes to the switch. This is to allow the jumper to be opened when in the RC-850 controller position. Also, remove JU-IO and attach wires from the jumper holes to the switch. Attach a wire from JU-IO hole that is on the pad of 0-18, to the center contact of switcht and the other wire to the side of the switch that will be open when In RC-850 position. Attach another wire from the other side of the switch to a ground foil.

Back Panel Board Wiring

Using shielded wire, connect the center conductor to pin i7 of the Audio-Squelch strip (Position 13), and the shield to pin 14. This wire will be run to a second switch (Radio Shack #275-324) that can be mounted in a convenient place. This switch breaks the audio.

Connect another shielded wire from pin 17 on the Squelch Gate strip (Position 7) shield to pin 23. Run this wire to the switch. Wire the switch so that this circuit is open in RC-850 position.

Also, at pin 17 of the Squelch Gate strip there is a printed circuit that goes off at an angle - this circuit needs to be cut between the pin and solder spot on board.

Cabling to Controller

Prepare two shielded cables with phono plugs on one end for connection to the controller (cables can be acquired from Radio Shack). Connect as follows:

Center conductor to Position13 strip pin 17, and shield to pin 14. This cable goes to "RX" phono plug on back of the controller.

Center conductor to Position 7 strip pin 17 (you can cut off the shield from this cable). This cable goes to the "TX" phono jack on the controller.

Using a three wire cable we can now connect the COS and PTT lines and ground:


E8 (ground) on the backplane to controller Digital I/0 connector pin 25.

E5 (Repeat PTT) on backplane to Digital I/0 connector pin 7.

Position 13 strip pin 2O (SQ indicate) to Dlgltal I/0 connector pin i7.

If you have the TIME OUT card, set the jumper to disable timeout. The REPT LEVEL control on the Squelch Gate card will be used for the exciter level adjust and should be set to the value on the sticker from the factory.


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