Analog modem emulator?

'Bit banging' is a common term for doing the serial<->parallel conversion in software (using shift instructions, etc) rather than using a hardware UART (or ACIA, etc) chip. It doesn't necessarily only refer to RS232 interfaces, it's quite common to say something like "I'm bit-banging the I2C protocoi on a couple of the port A pins of that PIC". The bit-banger that I refered to here is whichever of the Apple cards didn't use a UART chip. There seem to be 2 approximately contemporary cards, and I am sure to get them the wrong way round, but here goes : The Serial Interface, which contained a few TTL chips, and a couple of PROMs. This is the one I call the bit-banger The Coommunication card which contains a 6850 ACIA (similar to a UART). -tony