DTR Problems

generous at dgis.UUCP generous at dgis.UUCP
Sun Mar 1 01:08:51 AEST 1987


In article <2603 at phri.UUCP> roy at phri.UUCP (Roy Smith) writes:
>In article <1995 at emory.UUCP> km at emory.UUCP writes:
>> We have been having the following problem on 4.3BSD (acutally the
>> Mt Xinu release) [...] Getty does not always raise DTR on its port.
>
>	For some more conventional suggestions, check the dmf flags in your
>config file to make sure modem control is {en,dis}abled on the right lines
> ...
>you're using a mix of Emulex CS-21's and DEC DMF-32's, remember that only
>the first two lines on the DEC board have modem control, and that while all
>the Emulex lines do, it doesn't quite match that on the DEC board.
>

About 16 months ago, I ran into the same problem that km at emory had with
the modem control signals on a DEC DMF-32, under More/bsd (Mt. Xinu's 4.2 bsd),
running on a 11/750.
I eventually discovered the same two remedies that roy at phri mentions:

     1) you need the proper flags set in your /sys/conf/HOST file
	 (and then make sure you run config, make depend, make ... :-)
     2) make sure that you only use the first 2 ports

But I also discovered one more thing was needed to get the ports to work:

     3) You needed to use a program called "/etc/ttyconfig".
	This is a Mt Xinu's unique program? (as far as I know), and 
	it allowed the control some on those signals.  I am telling this
	all from memory, as I don't have access to this host anymore.
	I also remeber having a hard time finding any info on "ttyconfig",
	as there wasn't a man page available.  (Maybe Ed Gould can tell
	us more about it?)

By the way, the version of the DMF-32 driver that we had from Mt. Xinu
also supported the parallel port (we had a printer attacher to it).  
Has any one out there written a driver to also support the synchronous port?
Hope this helps:

-curtis-
======================================
Curtis C. Generous
Lawrence Livermore National Labs
ARPA: generous at lll-tis-b.ARPA
UUCP: {seismo,vrdxhq}!dgis!generous



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