Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!ames!hao!husc6!psuvax1!vu-vlsi!cbmvax!grr
From: grr@cbmvax.UUCP (George Robbins)
Newsgroups: comp.dcom.modems
Subject: Re:  EIA Flow Control
Message-ID: <3367@cbmvax.UUCP>
Date: 25 Feb 88 14:38:00 GMT
References: <8802222331.AA03700@ucbvax.Berkeley.EDU> <825@vixie.UUCP> <3158@phri.UUCP>
Reply-To: grr@cbmvax.UUCP (George Robbins)
Organization: Commodore Technology, West Chester, PA
Lines: 39

In article <3158@phri.UUCP> roy@phri.UUCP (Roy Smith) writes:
> In article <825@vixie.UUCP> paul@vixie.UUCP (Paul Vixie Esq) writes:
> [regarding using RTS/CTS as flow control, contrary to what RS-232 says]
> > It very desperately needs to become an official standard, since it is in
> > very wide use as an unofficial one. [...]  In short, Everybody Does It
> > This Way, so could somebody please document it in an IEEE or ANSI spec
> > somewhere?
> 
> 	Hear, hear!  I don't know how common half-duplex modems (which need
> RTS/CTS to work as RS-232 says they should) really are, but in the 13 or so
> years that I've been using modems, I have never (knowingly) used or seen a
> single one...

If you've never seen one, then you have a case of tunnel blindness from
working with dial-up async connections to the exclusion of the greater
world of datacomm.  8-)

There are still zillions of half-duplex 1200 baud modems doing their
thing in the business world, and a whole regime of multi-drop and
two-wire leased-line controlled carrier applications.

What this means is you can't just arbitrarily change the standard
so that RTS has a radically different and pretty much incompatible
definition.  You could of course propose an alternate optional function
that happens to share the same pin(s).

You also need to define how the RTS and CTS pins are to be interpreted
in this new order.  Do they mean stop/abort character, stop at end of
current character or stop when the software gets around to noticing a
status change?  In the latter case, should there be any kind of
(optional) overrun/error indication defined?

I suppose proposal the the proper standards organization would be
in order, although the RS232 standard usually only gets changed after
everybody is acutally doing something different...

-- 
George Robbins - now working for,	uucp: {uunet|ihnp4|rutgers}!cbmvax!grr
but no way officially representing	arpa: cbmvax!grr@uunet.uu.net
Commodore, Engineering Department	fone: 215-431-9255 (only by moonlite)