I had something very similar with my radio as well where I couldn't get DOS to work. What I found I had to do was to enable Call Alert Decode (or Selective Call Decode) - basically the radio has to "do something" with MDC in order for DOS to work.
What kind of radios do you have? I'd be willing to look at your codeplug if I have the CPS for it. Another option would be to post screenshots of the conventional personality and the MDC system.
I had something very similar with my radio as well where I couldn't get DOS to work. What I found I had to do was to enable Call Alert Decode (or Selective Call Decode) - basically the radio has to "do something" with MDC in order for DOS to work.
