I've not seen a PC without an audio codec since the early '90's. I've never seen a cellphone without one. Just what did you think that "chip" on the audio circuit is?

Mode 0 has nothing specific to do with a cellphone, except that the failure of the deisngers to use it and to use the extremely inefficient async protocol instead may indicate why cellphones are so unreliable. Async protocol wastes at least two bits per byte. Maybe that's why the entire system falls apart all the time. I've got one, but I hate 'em. They don't work when you need 'em. Mine has sat on my desk since I got it, except when I'm retained by the client who bought it for me.

TELECOM is a synchronous system. If they use async protocol, it's because they want to waste bandwidth and/or are too dumb to use synchronous protocols.

I think you need to go back and read what's been written previously. 11.0592 is fine if you have to use it. Mode 0 is a sampling mode. If you need to sample at 11.0592/12 it works fine. If you want to sample at some other frequency you have to use a different frequency. If you're using mode 0, which was not very practical with the one-clockers, you have to use an oscillator that's an appropriate multiple of the rate at which you want to sample. 11.0592 MHz is an appropriate rate at which to sample your async serial comm's in modes other than 0.

If you don't know what mode 0 is useful for, then don't use it.

Have you ever interfaced a tape drive with an MCU of any sort? In mode 0, if you sample at the right rate, you can capture the data and demodulate it in software. You can do that with floppy disks, too. The latest PC's don't even have those any longer. What if you want to read a hard-sectored 8" disk that someone desperately needs? How would you approach that problem? I can assure you, async modes won't help much.

RE