We personally have retired the GM300 and Maxtrac radios from repeater use due to the fact most of the radios have had lots of use.. Those radios have gone through heavy use over the past 12 to 13 years and are no longer in production.. Some times it becomes difficult to find those particular radios as well.. Now as far as the Technical details on the 16 pin adaptor I have found CM200 and CM300 with 16 pin adaptor and pin 8 programmed for csq/tone etc.. seems to work fine for both of our repeaters.. UHF repeaters are more simpler to set up than VHF repeaters reason is in UHF you can probably depending on where your tower site is located get away with a mobile duplexer cheap there usually around 130 dollars or so.. In VHF it is a 600khz spread and problems of loop back issues can occur very easily especially with cables duplexers many other things if incorrectly installed.. We have gone through 2 different manufactures now for duplexers and still have had issues with the transmitter getting into the receiver our personal next step is to double check the tuning of our used Sinclair 6 cavity duplexer and possibly putting a Bandpass filter for our RX side just to see if that might help with the duplexers installed as well.. Good luck on the installation and enjoy! I use DMK Engineering URI with 16 pin adepter from uricables.com Repeater adapter with CM200s..