Path: utzoo!mnetor!tmsoft!torsqnt!lethe!yunexus!ists!helios.physics.utoronto.ca!news-server.csri.toronto.edu!cs.utexas.edu!usc!samsung!uunet!mcsun!hp4nl!htsa!maestro!jand From: jand@maestro.htsa.aha.nl (Jan Derriks) Newsgroups: comp.sys.hp Subject: modem(7) DTR question HELP! Keywords: modem, callin, callout, uucico Message-ID: <2757@maestro.htsa.aha.nl> Date: 19 Feb 91 13:20:08 GMT Sender: bin@htsa.htsa.aha.nl Organization: AHA-TMF (Technical Institute), Amsterdam, The Netherlands Lines: 40 HELP ! After reading modem(7) 77 times, I'm still having trouble with the callin/callout/acu lines regarding DTR behaviour. PROBLEM: when an open(2) on the dial-out line (cul2p0) fails because there is no connection yet (DCD inactive), the DTR signal becomes INACTIVE ! Is this normal ? When the open succeeds and the line is closed, the DTR is dropped and re-raised. We need DTR to reset the modem and to answer incoming calls. System: HP-UX htsa A.B7.00 C 9000/835 18329 Details: I use the three terminal type files /dev/cua2p0 to dial and make an outgoing connection /dev/cul2p0 to talk once the connection is set up /dev/ttyd2p0 where the getty is waiting for DCD to come just as the manual describes. The CCITT mode ("use it if you are living in Europe, says SAM") hung up all the lines until a system reboot, so I chose the 'SIMPLE' modem control mode (recommended for people in USA or Canada). If anyone knows how to fix a hanging CCITT device driver without a reboot I'd be pleased to hear from her/him. Setting+dropping didn't help. Simple mode is an improvement, but look what happens if uucico dials out (using dialers script, not dialit.c) and fails: 1. uucico acquires /dev/cua2p0, the ACU line to dial the number. 2. suppose the line is busy and we don't get DCD 3. uucico tried to open /dev/cul2p0 anyway (why?) and fails, 4. causing DTR to drop and stay inactive, causing 5. the modem not to answer incoming calls. I now use a cron job to set DTR if it's not set but it seems to me that a failed open shouldn't keep DTR low. What's going wrong ? Jan Derriks. -- Brought to you by Super Global Mega Corp .com