Intercom with call inductors, want to mux the audio and tone down the same line. This is what im looking at. One unit sends a tone down a audio line with normal voice present. The other units down the line decodes the tone. This tone make a led light when it see the tone. Different tones turn different leds on or off. Audio filter keeps the tone from being heard.
Audio Line:40hz 60hz 80hz 100hz
Tone----> Unit ----> Unit ----> Unit ----> Unit -----> etc..
80hz off off on off
I was hoping to do this with a PIC because of less parts to keep the cost down.
Or maybe i only send on tone out in pulse and decode that... Hmmm. Toughts
Can someone help. Thanks
