Mike Morris WA6ILQ wrote: > I'm looking for a schematic for a EF Johnson DTMF > microphone, model number 589-7600-022. > > Also, does anybody know what radio they are used on? > And the pinout of that radio's microphone jack? > > Mike WA6ILQ
Which connector does it have, Mike? Is it the modular, or a 5-pin round DIN connector? The 5-pin is for older radios, PPL, SDL, various Fleetcom's, and so on, that had a non-amplified 600 ohm dynamic.The modular is for the newer Challenger (and newer) that use a pre-amped mic, similar to Motorola and newer GE. I think there may be some variation in the modulars, with both a 6-pin and an 8-pin, but I think the 6-pin will work on the 8-pin radios OK. -- Jim Barbour WD8CHL
