XTL1500 to CM300 Crossband Cable

[Blisstick]

I've been asked to link two base radios to allow the receive on a XTL1500 to be transmitted on a CM300 (crossbanding one way only).

Here's where I'm at with a design using the accessory ports on both radios:
XTL1500 Pin 1 Ground to CM300 Pin 7 Ground
XTL1500 Pin 21 Receive Filtered Audio Out to CM300 Pin 2 External Mic Audio
XTL1500 Pin 13 Channel Activity to CM300 Pin 3 External Mic PTT

- Should I use Pin 2 or Pin 5 for Audio input on the CM300? Assume Pin 2 as only voice audio range is needed, but I'm uncertain about different input levels shown in the manual.

- Is it the Channel Activity pin from XTL1500 that should key up the PTT on CM300?

Surely this is very basic for many of you who build accessory cables regularly... I'd like your help to get this right the first time! Thanks!

[Blisstick]

I'm tempted to just make up the cable and try it. Can anyone advise on risk of harming either radio by crossing these pins without adding other components to try to match/control input levels?

[ve3nsv]

You should be fine with that configuration. Just play with the accessory mic gain on the CM200 to achieve the desired repeat deviation.

[Blisstick]

Thanks. I'll report back with results for anyone else facing a project like this in the future.

[Blisstick]

Fired it up today and all is working well.