Douglas Quebbeman wrote:
>
> You left out 75 baud...
>
> And IIRC, didn't the IBM 2741 teleprinter use something like
> 147.5 baud?
> > -----Original Message-----
> > From: Mike Ford [mailto:mikeford_at_socal.rr.com]
> > What was the progression in modems? Was it 110, 135, then
> > 300, or were the
> > first two speeds pre modem technology?
You also left out 28.x or was it 27.x), 34.5, and 2 different rates in
the 50's. Sorry I went through my asm code and couldn't find the references
to the speeds. The 6551 started at 50 and went up but I think we got the
oddball rates using external clocking. The newspaper industry used these
rates. A 1918 motorized Underwood typewritter would use dry loop and the
28.x/27.x rate. It was still supported in the mid 80's when it was retired
when no new parts were available.
BTW all of these rate (less than & equal to 300) used Bell 103 when
communicating via a modem.
Reminds me of the time we played with a printing machine designed in the
1940's. Used a centronics like parallel interface but +/- 25 volts, weird
timing for the pulses and smelled of vinegar!
--
Linux Home Automation Neil Cherry ncherry_at_home.net
http://members.home.net/ncherry (Text only)
http://meltingpot.fortunecity.com/lightsey/52 (Graphics)
http://linuxha.sourceforge.net/ (SourceForge)
Received on Fri Oct 27 2000 - 16:46:38 BST