Although not a question specific to microcontrollers, I'm going to ask here anyway in hopes that someone has tried this and can tell me if it works. (Actually, I'll be using a 9S08SH8 and a CMX867A DTMF/FSK chip so this should be kinda on-topic.)
During a phone call I want to send a caller ID packet from my device to a distant phone with a caller ID display. Will that work? I notice that when I'm on the phone and get a call, my ear gets blasted into near deafness by the incoming caller ID data. It is extremely loud. Is this necessary for me to send and display a caller ID string, or do you think I can do it with "normal" audio levels? Or is there anything else that may prevent this from working?
My objective is to interrogate my uC device with a standard caller ID phone and display the results, without using any special hardware on the caller's end (other than a caller ID phone handset).
Thanks for any comments & suggestions.