Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!yetti!geac!daveb From: daveb@geac.UUCP (Brown) Newsgroups: comp.dcom.modems,news.sysadmin Subject: Re: Hardware Protocol Message-ID: <1172@geac.UUCP> Date: Tue, 18-Aug-87 13:36:06 EDT Article-I.D.: geac.1172 Posted: Tue Aug 18 13:36:06 1987 Date-Received: Wed, 19-Aug-87 05:45:14 EDT References: <192@caeco.UUCP> <2849@phri.UUCP> <1103@laidbak.UUCP> Reply-To: daveb@geac.UUCP (Dave Collier-Brown) Organization: The little blue rock next to that twinkly star. Lines: 42 Summary: CTS/RTS was actually bidirectional (by kludge?) Xref: mnetor comp.dcom.modems:818 news.sysadmin:335 In article <2849@phri.UUCP> roy@phri.UUCP (Roy Smith) writes: >In article <192@caeco.UUCP> murf@caeco.UUCP (Steve Murphy) writes: >> The Sun 3/160 (and all the sun 2's and the 3/110's also) cannot hardware >> handshake AT ALL. [...] Now, if I worked for Sun, I'd blush, because this is > > Arghhhhh! Maybe the reason Sun's RS-232 ports don't do RTS/CTS >handshaking is because if they did, it wouldn't be RS-232. As defined in the >standard, RS-232 has no flow-control. Well, I remember programming half-duplex modems, and they did handshake bidirectionally using CTS/RTS. I won't say that they did it *elegantly*, but they did do the following. Talk, talk, talk... <------------ *CTS I'd like to talk. RTS ------------> <------------ CTS Ok, you talk. *RTS ------------> Huh? Oh, flow control... <------------ *CTS Talk, talk, talk... Talk, talk, talk... <------------ *CTS I'd like to talk. Ok, you talk *RTS ------------> Huh? Flow control! <------------ CTS [this isn't kosher] RTS ------------> Talk, talk, talk... Note that asserting CTS without RTS is not part of the standard, and so is subject to misinterpretation and non-implementation. And its forgotten later, so we have to re-invent it... I *DO NOT* know the meaning later (4XX) standards applied to these lines. dave (I HATE reinventing wheels) collier-brown -- David Collier-Brown. | Computer Science Geac Computers International Inc., | loses its memory 350 Steelcase Road,Markham, Ontario, | (if not its mind) CANADA, L3R 1B3 (416) 475-0525 x3279 | every 6 months.