Batboard

motorola has a new CM300 i guess it replaced the gm300
the cable is different from what i head....anyone know how to make a cable for this radio.
thanks,
please email me at hamradio18@hotmail.com

http://batboard.batlabs.com/viewtopic.p ... ight=cm300

A post by WAVETAR gives the answer.

It amounts to being the same cable as the GM300 etc., but with the addition of pin 6 and 8 jumpered together at the radio end.

I believe this should be pins 1 and 3 since Motorola seems to count the connector pins the other way around.
So connecting the normally unused pin 1 to pin 3 (the hook switch pin) does it. You can leave this jumper in for programming other radios without problems.

Nand.

Repeater-Builder recommends a 100 ohm resister be used instead of jumper as the Maratrac has Battery voltage instead of 9V on that pin;
"However, you WILL have a problem if you use this modified cable on a MaraTrac. This is because the MaraTrac has full battery voltage (13-14V) on that pin (they number it pin 1) at basically unlimited current (well, until something burns up) and the Hook input on the logic board has a 10V Zener diode protecting it, unlike the PTT input which has a 27V Zener diode protecting it. To prevent burning anything out, I recommend that you use a 100 ohm 1/4 watt resistor instead of plain wire for the jumper between the modular plug pin 8 and pin 6."

This thread is 13 years old.

We were building an adapter TODAY! I have Maratracs in service. I would hate to see someone damage one.