I’m attempting to recreate the mobile rotary phone but I’ve been stuck for a few days trying to get the mic to work. I can make calls, receive calls and the GM862 unit can receive audio just fine (e.g. the speakers work) but the mic for some reason does not work. I’ve tried a handset which I know to work and attached it to the GM862 unit but still I am having trouble getting the microphone working.
I followed the mic diagram in the SF tutorial with the 10K resistor and the 10uF cap but doesn’t work. I looked it up online, the rotary phone which I bought was from the 1950s and most likely it has a carbon microphone. Does anyone know if this is what’s preventing it from working? Though, I attached a relatively modern electret mic but still doesn’t work.
Any advice appreciated. Thanks.