Originally Posted by firefive76
You have to have the adapter for the CM200, CM300, PM400 radios. The GM/CDM cable will work only with the adapter attached to it.
That may be changing.
Another guy with similar issues just bought a new USB cable for the CM's/PM's and it worked fine without the 1 to 3 adapter. At this point, you'd probably have to examine the cable closely to see if there is a jumper at the RJ45 end. Even if there isn't, if all the pins are populated with wire, it's possible the jumper has been added at the other end.
The only way to be really sure is to try it. If it will read the radio without the adapter then you are good to go.