I recently moved into a home with an old M&S Model 350 intercom. The Speakers all seem to work ok, but the master unit is in bad shape. It doesn't turn off the program/set time buttons do not work.
I found the DCM3-4 unit online as a retrofit replacement. This looks like it'll work, but everything I see regarding the installation indicates that I have to replace ALL the Speaker stations as well. After inspecing one of the speaker I'm puzzled as to why. The unit is extremely simple, the speaker with a switch to toggle between a speaker and mic setting.
Can anyone tell me why you would make the old speaker incompatible with the old system. Thanks