[[Media:CDM Cable.pdf|CDM Cable from Kurt Meltzer]] ex-WB9KNX, now KC4NX - Cable 83 has only one output to use for either COS or CTCSS. Use another cable if you need both COS and CTCSS.
[http://www.repeater-builder.com/motorola/maxtrac/maxtrac-index.html All about GM300 Radios]
Connections are fairly simple but can be hard to determine which is the correct one to use. This [http://www.repeater-builder.com/motorola/maxtrac/maxtrac-option-plug.html link] is a good place to start.