At least regards EX and C version its the shorter cable length for the ex90,
I would not like to have 7,5m cable on my desk, not sure whats the difference with the MX version.
It might have been easier if it would have been either a simple POE device or
the cables would have been more modular.
The ex also have a handset , the mx a long cable (not sure if you could
hook up a handset there).
The intention of a MX200 is to use it easy with plug and play in a small to medium size room,
there also the approach with the long cable and a direct physical connection incl power to
to the codec makes sense as well.
I did not try it and its on your own risk, but I could picture that the MX version works with
the power injector, maybe you hav to disable the secondary port.
I could also picture that the C Series version would work on it.
If you tried it and it did not work then it might not work. If you do not get a better answer,
talk to your Cisco partner or contact, maybe they can say something.
If you get additional info, please let us know here as well.
Please remember to rate helpful responses and identify helpful or correct answers.
