I decided to try and add a remotely controlled VHF radio to my repeater controller for use as a remote base radio. I’m using an Arcom RC210 controller and a Motorola CDM1250 on Port 3 of the controller. I wanted to use a frequency agile radio, but there don’t seem to be any in current production that fit my need. Below I will show what I did to get this setup to work for me.

I only wanted a few vhf frequencies for my setup. The Motorola CDM has the ability to channel steer up to 31 channels from what I’ve read. I will be steering 8 channels. you will need to program the accessory pins on the rear of the radio. I utilized pin 6 for Channel select 1, pin 8 for Channel select 2, pin 14 for Channel select 3. By grounding these pins in a certain order you can change channels on the radio. Below I will show a chart of all the pins I used for this. I am also utilizing an opto-isolated relay board to control the ignition sense to turn the radio on and off. These pins will be controlled with the Logic in/out pins of the Arcom Controller.

Programming of the controller First I programmed macros to change the state of the I/O pins, then I made message macros with the frequencies that I programmed into the radio, Channels 1-8, and when I call a macro to bring up that channel, The logic state changes, plays a message and moves the radio to the desired channel.

Channel Steering a Motorola CDM for use as a remote base connected to an Arcom RC210 Repeater Controller

Note, if you utilize an additional Channel Select pin you will be able to steer up to 15 channels.  Additionally, if you add a 5^th you will be able to steer up to 31 channels.

Binary code table L=Low/Grounded         H=High/Floating

CS = Channel Select

Channel	CS 3	CS2	CS1
Front Panel	H	H	H
1	H	H	L
2	H	L	H
3	H	L	L
4	L	H	H
5	L	H	L
6	L	L	H
7	L	L	L

Pin #	Description	Data Dir.	Debounce	Act. Level
6	Channel Select 1	Input	No	Low
8	Channel Select 2	Input	No	Low
14	Channel Select 3	Input	No	Low
12	PL and CSQ Detect	Output	No	Low
3	PTT	Input	No	Low
10	Ignition Sense	Input		High

Arcom RC210 I/O Connections

PIN	NAME	DESCRIPTION
9	UF1	Logic Output 1
10	UF2	Logic Output 2
11	UF3	Logic Output 3

 These are switched outputs that can be commanded on or off.  When an output is High, it is actually an open drain JFET.

Macros to pull the pins low.

Macro 73= 100 101 102 470 162

UF 1 off, UF 2 off, UF 3 off, Play Message macro-51, Speech out port 1

Do similar for all channels you have programmed.

Wiring it up

CDM ACC CONN.	USE	ARCOM PORT PIN #	ARCOM I/O PIN #
2	MIC AUDIO	4
11	RECEIVE AUDIO	5
7	GROUND	6
12	PL DETECT	2
3	PTT	3
10	IGNITION SENSE		**To Relay then 15 UF 7
6	CH SELECT 1		UF 1- PIN 9
8	CH SELECT 2		UF 2- PIN 10
14	CH SELECT 3		UF 3- PIN 11

**Note I am using a 1 channel relay module that has optocoupler isolation and supports high- or low-level trigger.

I am using the Ignition sense on the CDM to be able to turn the radio on and off.  I am utilizing a 1 channel, 12-volt relay board which I purchased on Amazon. I programmed the radio for ignition control in the Radio Configuration -> Accessory Configuration page in the software.  In the drop-down menu I selected ON/OFF & IGNITON.  This way I can still manually turn on the radio by the front button if I need to, as well as via the ignition control wire.

 This relay board is what is used to complete a circuit when a signal is sent to the controller.  When IN receives a signal from the controller, it will connect NO to COM and complete the circuit.  Thus, turning on the radio.

You will need to make a macro to turn on UF7 and another to turn it off.  Then make 2 messages to say radio on and radio off and add it to the macros.

RC210 LOGIC OUTPUT	STATE	ACTION	MACRO #	MESSAGE #
UF 7 PIN `15	L	RELAY ON	86	61
UF 7 PIN 15	H	RELAY OFF	87	62

NO= PIN 10 of radio

Com= 12 volts + from power supply

IN= Trigger signal from Arcom Pin 15 (UF7)

DC- = Negative 12 volts

DC+ = Positive 12 volts

Jumper is to the L position for active low.

I am going to leave the radio on channel 8 at the start, that is considered FRONT PANEL as shown in the table above. 

This way I can direct the radio to channel 1-7 and still be able to use channel 8 as well.  I also created a macro to shut off the radio when I am done using it and it will then set all pins to High and revert it back to the front panel channel.

481 100 101 102 106 = Play message macro-62, UF1,2,3,7 off.

Parts Used

Digikey Part Numbers:

20 Pin Connector 104422-2-ND

16 Pin Connector 104422-1-ND

Contact Pins 1-87309-3-ND

Amazon:

AEDIKO 10pcs Relay Module DC 12V Relay Board 1 Channel with Optocoupler Isolation Support High or Low Level

---