From: Bob Supnik Newsgroups: alt.sys.pdp10,alt.sys.pdp11 Subject: DZ behavior in BSD Date: Wed, 03 Oct 2001 10:58:50 -0400 Organization: Posted via Supernews, http://www.supernews.com Message-ID: X-Newsreader: Forte Agent 1.8/32.548 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Complaints-To: newsabuse@supernews.com Lines: 14 Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news-ge.switch.ch!news.maxwell.syr.edu!newsfeed.stanford.edu!sn-xit-01!sn-post-01!supernews.com!corp.supernews.com!not-for-mail Xref: chonsp.franklin.ch alt.sys.pdp10:6992 According to Fred an Kampen, PDP-11 BSD treats the modem control on the DZ very differently than the simulator expects (including all prior versions). Fred says that the code blindly sets DTR and then polls for DCD (carrier detect) as its indicator of an incoming call... it never looks at RING, which was a "Bell specific" feature. This would require a change in the "accept connection" code. Right now, if modem control is enabled, the code simply sets RING. Instead, it would check DTR. If DTR is set, DCD is set; if DCD is clear, RING is set. Insights from modem-knowledgeable folks appreciated... /Bob ###### Path: chonsp.franklin.ch!not-for-mail From: Neil Franklin Newsgroups: alt.sys.pdp10,alt.sys.pdp11 Subject: Re: DZ behavior in BSD Date: 03 Oct 2001 21:24:07 +0200 Organization: My own Private Self Lines: 66 Message-ID: <6u7kucmsrs.fsf@chonsp.franklin.ch> References: NNTP-Posting-Host: chonsp.franklin.ch X-Trace: chonsp.franklin.ch 1002137049 728 10.0.3.2 (3 Oct 2001 19:24:09 GMT) X-Complaints-To: news@chonsp.franklin.ch NNTP-Posting-Date: 3 Oct 2001 19:24:09 GMT X-Newsreader: Gnus v5.7/Emacs 20.4 Xref: chonsp.franklin.ch alt.sys.pdp10:6998 Bob Supnik writes: > According to Fred an Kampen, PDP-11 BSD treats the modem control on > the DZ very differently than the simulator expects (including all > prior versions). Fred says that the code blindly sets DTR That would be the getty program doing an open("/dev/ttynn") system call, where the tty driver then sets DTR for the line nn. DTR is quasi the "I am here, ready to take logins" signal. > and then > polls for DCD (carrier detect) as its indicator of an incoming call... That is the open() and the driver behind it, waiting (usually for an interrupt, not polling) and then returning once DCD is seen. Carrier is here, so there must be a user arrived to demand service. This is the standard behaviour of any Unix variant I have heard of, given in all manuals how to wire RS232 cables. > it never looks at RING, which was a "Bell specific" feature. What RING? If you have got an directly connected terminal (with cross over cable, no modems) there is nothing that could RING. Just DTR of the originating host (activated by uses "connect" program) wired to DCD of the recieving host, to announce that you want to come in. I usually also wire DTR to DSR, for in case some random OS also wants that. No DSR means no Modem there, may inhibit connections. > This would require a change in the "accept connection" code. Right To simulate more precise, what the modem or cross cable does. > now, if modem control is enabled, the code simply sets RING. Instead, > it would check DTR. If DTR is set, DCD is set; if DCD is clear, RING > is set. I assume you wanted to write there "if DTR is clear, RING is set". That would translate to putting in OS expectation dependant code, which is IMHO a bad idea. Why not be more robust and simply allways set RING and DCD and DSR. This should satisfy any OS, even ones neither you nor I have heard of. Or make it an settable "port wiring option" in the SIMH configuration. Although this will increase users with config trouble. Perhaps default to RING + DCD + DSR and allow RING-only and DCD-only for those with picky OSes. Or set an pattern 4=RING, 2=DCD, 1=DSR, which is initially set to 7. > Insights from modem-knowledgeable folks appreciated... Neil "wired too many RS232es" Franklin. -- Neil Franklin, neil@franklin.ch.remove http://neil.franklin.ch/ Hacker, Unix Guru, El Eng HTL/BSc, Sysadmin, Archer, Roleplayer - Intellectual Property is Intellectual Robbery ###### From: Arthur Krewat Newsgroups: alt.sys.pdp10,alt.sys.pdp11 Subject: Re: DZ behavior in BSD Lines: 53 Message-ID: <3BBB74B4.DC78D192@bartek.dontspamme.net> References: <6u7kucmsrs.fsf@chonsp.franklin.ch> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailer: Mozilla 4.7 [en] (X11; I; SunOS 5.8 i86pc) X-Accept-Language: en Date: Wed, 03 Oct 2001 20:32:46 GMT NNTP-Posting-Host: 24.186.100.134 X-Trace: news02.optonline.net 1002141166 24.186.100.134 (Wed, 03 Oct 2001 16:32:46 EDT) NNTP-Posting-Date: Wed, 03 Oct 2001 16:32:46 EDT Organization: Optimum Online Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!news-ge.switch.ch!news.maxwell.syr.edu!cyclone2.usenetserver.com!usenetserver.com!news01.optonline.net!news02.optonline.net.POSTED!not-for-mail Xref: chonsp.franklin.ch alt.sys.pdp10:7009 Neil Franklin wrote: > > Bob Supnik writes: > > > it never looks at RING, which was a "Bell specific" feature. > > What RING? If you have got an directly connected terminal (with cross > over cable, no modems) there is nothing that could RING. Just DTR of > the originating host (activated by uses "connect" program) wired to > DCD of the recieving host, to announce that you want to come in. RING is used on dialins to signal the OS someone is dialing in. If the modem is not set to auto-answer, the OS must tell the modem to pick up, which used to be pulling DTR high, now it's usually giving the modem the string to pick up (hayes: ATA). If the modem is set to auto-answer, DCD will come up when it's done negotiating. > I usually also wire DTR to DSR, for in case some random OS also wants > that. No DSR means no Modem there, may inhibit connections. I have seen instances where this is a problem. If DSR is not high, the OS thinks there's no modem, so why bother raising DTR? DSR should be ready when the modem is able to receive commands or give carrier, or anything else. In the case of SIMH's DZ11, I think DSR being high all the time would be a good thing. I still have no luck with dataset support turned on for TOPS-10 and the SIMH DZ11, and I wonder if that's why, no DSR or DCD. I can't think of any specific examples of this, but I do remember this causing me problems with some older equipment somewhere (maybe printer?) > Why not be more robust and simply allways set RING and DCD and DSR. > This should satisfy any OS, even ones neither you nor I have heard of. > > Or make it an settable "port wiring option" in the SIMH configuration. > Although this will increase users with config trouble. > > Perhaps default to RING + DCD + DSR and allow RING-only and DCD-only > for those with picky OSes. Or set an pattern 4=RING, 2=DCD, 1=DSR, > which is initially set to 7. This sounds like the right thing to do - make it configurable with a default of RING+DCD+DSR - who knows, someone may want to dialout with it and they would need the proper sequence of events. > Neil "wired too many RS232es" Franklin. me too... aak ###### From: Brian Inglis Newsgroups: alt.sys.pdp10,alt.sys.pdp11 Subject: Re: DZ behavior in BSD Date: Mon, 22 Oct 2001 21:08:50 -0600 Organization: Systematic Software Lines: 40 Message-ID: References: Reply-To: Brian.dot.Inglis@SystematicSw.ab.ca NNTP-Posting-Host: h-207-148-130-74.dial.cadvision.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Trace: news3.cadvision.com 1003806533 4566 207.148.130.74 (23 Oct 2001 03:08:53 GMT) X-Complaints-To: news@cadvision.com NNTP-Posting-Date: Tue, 23 Oct 2001 03:08:53 +0000 (UTC) X-Newsreader: Forte Agent 1.8/32.548 Path: chonsp.franklin.ch!pfaff.ethz.ch!news-zh.switch.ch!newsfeed-zh.ip-plus.net!news.ip-plus.net!news.tesion.net!news.belwue.de!news.uni-stuttgart.de!news.stealth.net!207.35.177.252.MISMATCH!nf3.bellglobal.com!sunqbc.risq.qc.ca!nntp.cadvision.com!207.228.64.17.MISMATCH!not-for-mail Xref: chonsp.franklin.ch alt.sys.pdp10:7264 On Wed, 03 Oct 2001 10:58:50 -0400, Bob Supnik wrote: >According to Fred an Kampen, PDP-11 BSD treats the modem control on >the DZ very differently than the simulator expects (including all >prior versions). Fred says that the code blindly sets DTR and then >polls for DCD (carrier detect) as its indicator of an incoming call... >it never looks at RING, which was a "Bell specific" feature. > >This would require a change in the "accept connection" code. Right >now, if modem control is enabled, the code simply sets RING. Instead, >it would check DTR. If DTR is set, DCD is set; if DCD is clear, RING >is set. > >Insights from modem-knowledgeable folks appreciated... DSR says the DCE is on. DTR says the DTE is on. RI says I have a call incoming. DCD says the call connected. RTS says the DTE is ready for data. CTS says the DCE is ready for data. Simplified wording for RS232/V.24. DTR and DSR should probably always be on. Connection should assert RING and DCD. RTS should be asserted by the port, and the modem should then assert CTS. DTR and RI are apparently only required for switched network service (dialup). From "Technical Aspects of Data Communications", John E. McNamara, Digital, 1977, 0-932376-01-0. HTH. Thanks. Take care, Brian Inglis Calgary, Alberta, Canada -- Brian.Inglis@CSi.com (Brian dot Inglis at SystematicSw dot ab dot ca) fake address use address above to reply tosspam@aol.com abuse@aol.com abuse@yahoo.com abuse@hotmail.com abuse@msn.com abuse@sprint.com abuse@earthlink.com abuse@cadvision.com abuse@ibsystems.com uce@ftc.gov spam traps