> > For modem to modem communications, start and stop bits were used
> > up through 2400 baud when one bit = one tone. The method of one
> > bit = one tone was dropped for other forms of encoding when modems
> > started supporting connection speeds in excess of 2400 baud.
> I assume you mean 2400 bps modems, i.e., v.22bis? Admittedly, it's been a
> while since I used one, but my recollection is that 2400 bps modems operate
> at 600 baud, with 4 bits/baud using QAM.
This matches my recollection. I think it was 1200 bps that was the
last 1 bit per baud modem.
Yes and no. The Bell 202 was 1200 bps, one bit per baud, half duplex
on a switched line. The Bell 212 was 1200 bps, 600 baud, 2 bits per
baud, full duplex. So was the Vadic 3400, which preceded the 212.