flow-control on 3B2/EPORTS

Stephen J. Friedl friedl at vsi.UUCP
Wed Mar 16 18:32:20 AEST 1988


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*********** If you don't have a 3B2 with EPORTS hit "n" now...
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Netlanders,

     This must have been asked a hundred times with respect to
Trailblazers (we just got ours!) but my questions are more
general.  Like many 3B2 owners, we eagerly awaited the EPORTS
card that support hardware flow-control but we are somewhat
disappointed.  For running a serial printer with DTR it is great
but we're having difficulties with MNP modems, the 'Blazer, and
multiplexors.

     I contend it is a bug that you can pick HFC *or* XON/XOFF,
when in fact it would be really helpful to run both at the same
time.  Werer I setting up my system, I would run HFC between the
system and these devices, letting the hardware and the modem talk
to each other entirely transparently to everything else.  Then,
if I hit ^S on my terminal it will actually stop output rather
than echo and disable my keyboard (I *really* hate it when that
happens).

     Basically, hardware flow-control should be so deep in the
driver that your ioctl() just sets some bits in the serial
hardware and Unix is otherwise unaware of anything.  This lets
your MNP modem, Trailblazer, terminal or multiplexor do their own
things.  Then, on a higher level, the XON/XOFF can be used where
needed (over a non-MNP modem, a terminal without DTR flow-
control, etc.).  Besides, I can't have uucp turn on HFC and turn
it off when done.  Sigh.

     Has anybody else been frustrated with this?  Ideas?

     Steve
-- 
Steve Friedl, KA8CMY     ARPA/UUNET/CSNet: friedl at vsi.com       *Hi Mom*
{kentvax, uunet, attmail, {ucbvax, ihnp4, sun}!amdcad!uport}}!vsi!friedl
"It's sad we judge others by their actions and ourselves by our motives"



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