[net.news.sa] 2400 baud modems with 212 protocol?

brad@looking.UUCP (Brad Templeton) (03/19/84)

I wonder if it might be a good idea for 212 manufacturers to include
a 2400 baud, half duplex option on intelligent modems?  I am sure a lot
of people would be willing to buy them.  It could be done two ways.

The first way would be like 202, where the modem would transmit at
2400 baud (one modem xmit on both carriers, other receives on both) and
a special signal from the receiver - like a break, but perhaps a special
code in the sync bit pattern - would reverse the direction.

A simpler method is just to have the sender and receiver agree when to
switch. This is of use only for data communications like uucp.  Assuming
the switches could be done fast enough (or we had a different program)
we could get 2400 baud out of the existing equipment.

Anybody who's uucp phone bill was $100 a month would save $50 a month,
and that is about all these additions would cost.
-- 
	Brad Templeton - Waterloo, Ontario (519) 886-7304

dmmartindale@watcgl.UUCP (Dave Martindale) (03/19/84)

Uucp will NOT work with half-duplex modems - its protocol needs a full-duplex
channel.  You'd have to rewrite the packet driver to make it work on a
true half-duplex channel.  It would probably work fairly well, however,
on modems that provided a high bit rate in one direction and a low rate
in the other, by adding a few smarts to reverse the high-speed direction
on the modems when the master/slave relationship changed.