Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!ames!hc!beta!cmcl2!phri!roy
From: roy@phri.UUCP (Roy Smith)
Newsgroups: comp.dcom.modems
Subject: Re:  EIA Flow Control
Message-ID: <3158@phri.UUCP>
Date: 24 Feb 88 15:18:51 GMT
References: <8802222331.AA03700@ucbvax.Berkeley.EDU> <825@vixie.UUCP>
Reply-To: roy@phri.UUCP (Roy Smith)
Organization: Public Health Research Inst. (NY, NY)
Lines: 26

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.  What I have seen is full-duplex modems (or at least modems
which pretend to be full duplex), terminals, multiplexers, port selectors,
and computer ports running at speeds from 110 to 19,200 bps, often with
composite paths connecting several of the above at different bit rates, all
with a desperate need for reliable out-of-band flow control.  What I also
see are manufacturers who are acutely aware of this need groping around in
the darkness to try and coerce available signals into doing things they
were never intended to do.

	Clearly, there needs to be some official written standard which
includes hardware flow control for RS-232ish circuits.  Unofficial RTS/CTS
flow control sucks.  Unofficial DTR flow control sucks.  XON/XOFF flow
control sucks.
-- 
Roy Smith, {allegra,cmcl2,philabs}!phri!roy
System Administrator, Public Health Research Institute
455 First Avenue, New York, NY 10016