Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!gatech!bloom-beacon!eru!hagbard!sunic!mcsun!unido!opal!tmpmbx!utopia!robot!karl
From: karl@robot.in-berlin.de (Karl-P. Huestegge)
Newsgroups: comp.unix.xenix.sco
Subject: Re: need modem control lines info
Message-ID: <1990Nov22.000018.12178@robot.in-berlin.de>
Date: 22 Nov 90 00:00:18 GMT
References: <1990Nov19.151422.3584@bagend.uucp> <238@n4hgf.Mt-Park.GA.US>
Organization: K.-P. Huestegge, Sytemanalyse und Beratung, Berlin
Lines: 33

wht@n4hgf.Mt-Park.GA.US (Warren Tucker) writes:

>jan@bagend.uucp (Jan Isley) writes:
>>
>>I need some information on controling and determining the status of
>>modem control lines with SCO SYSV/386.  More precisely, I need to:
>>
>>1. Set DTR on.
>open the tty line
>>2. Set DTR off.
>close the line

>This is the only way to manipulate the DTR line.

>>3. Set RTS on.
>>4. Set RTS off.

>These are not directly manipulable.

>>5. Determine the state of CD.
>>6. Determine the state of CTS.
>These are not readable.

You might check RTS and CD together with the CLOCAL iocontrol. If You
unset CLOCAL and can't open the device in a suitable time, RTS or
CD are missing. If the open doesn't block, both signals are active.

You can still manipulate a blocking tty-Modemdevice with the fcntl (O_NDELAY)
feature.

-- 
Karl-Peter Huestegge                       karl@robot.in-berlin.de
Berlin Friedenau                           ..unido!fub!geminix!robot!karl