They both have the 20 pin accessory port in the back and a mic connector on the front panel. They are very different radios, but they do have some common features. Please stop mixing up the 1225 family and the CDMs. Does the programming cable plug into the front where the mic plugs in? The CDM1225 seems to have a 20 pin port in the back. I noticed the programming cable for the CDM1225 on ebay looks to have a CAT5 type data plug on one end, and a USB on the other, but I did not see anywhere on the radio photos (back side) where this cable would plug into a CDM1225. I just want something thats inexpensive, easy to program, has 40 watts of power, and is legal to operate on GMRS frequencies.
I take it these CDM varieties will program on a 64 bit modern USB based computer more easily? Also, do these varieties meet the part 95 legal operation criteria? If they do, then maybe I would like to check these out. You can find a CDM1250 or CDM1550 for around the same price - they're newer, have displays, will cover both GMRS and 70cm, and a larger channel capacity. A 16550-based serial port is highly preferred, I don't know how well the USB ones work computers of the right vintage for RSS usually have onboard 16550 serial. Virtualization may be an option but RSS needs Microsoft DOS to work. I'm not sure how the M1225 software runs on later computers. RSS doesn't run on modern hardware for the MT2000 I used Win95's DOS mode on a Pentium without issues. You'll have to find a copy of Motorola RSS for M1225 (not terribly hard to do) but that's definitely not the hard part.