Hayes modem for 3B2

Stephen J. Friedl friedl at vsi.UUCP
Fri Feb 26 15:53:13 AEST 1988


In article <2765 at chinet.UUCP>, randy at chinet.UUCP (Randy Suess) writes:
> This was discussed at length a while ago.  The problem is that the Hayes
> compatible modems do not handle CD and DTR properly, so that you
> cannot get a 3b2 to dial out AND have the hayes drop and raise CD
> properly for dial-in.  There are modems that work with the 3b2, and
> there is a hardware hack to make the hayes work.

     Those of you with 3B2s running System V Release 3.1 should
look in your 3.1 Release notes on page 2-67 under "Basic Networking
Utilities: Intelligent Modems".  AT&T has made Hayes go in+out
on the same line with carrier detect working the right way.
What the heck, I'll include a copy of the text:

[------------------begin Software Notes--------------------]

*Basic Networking Utilities: Intelligent Modems*

     Features have been added to the /usr/lib/uucp/Dialers and
/usr/lib/uucp/Devices files to prevent problems that occur when
using System 75s, System 85s, Hayes-compatible modems, and other
intelligent modems that do not keep Carrier Detect high all the
time [guess which of the above actually kicked off the fix :-) ].

Devices     Adding a ,M to the second field of an entry in the
            Devices file will cause the O_NDELAY flag to be set
            when the device is opened.  This prevents BNU soft-
            ware from blocking on the device while waiting for
            a CD.  The example below shows how to add the ,M to
            a Devices file entry for a devices connected to an
            automatic call unit for a Hayes modem.

            ACU tty11,M - 1200 hayes \T

Dialers     Adding \M before the chat script in a Dialers file
            entry will set CLOCAL, preventing any change in the
            CD lead from resetting the the state of the device
            [prevents SIGHUP - SJF].  Once the conversation has
            been established, \m will clear CLOCAL.  This will
            allow BNU to again monitor changes in CD (for exam-
            ple, to notice if the line drops).

            The example below shows how tyo add \M and \m to an
            entry made for a Hayes modem in the Dialers file

	hayes "=,-," "" \M\dAT\r\c OK\r \EATDT\T\r\c CONNECT \m\c

	+----+
	|NOTE|   For some devices, adding a \p after the \M may
	+-+--+   be necessary.
	  |
	  |

[end of Software Notes]

     For a long time we had troubles with this: the outgoing call
would not work unless cu or uucico debug mode was on.  "cu -d
911" worked fine but "cu 911" did not.  Tonight while writing a
previous note on this topic I rediscovered the |NOTE| above, ad-
ded \p to my scripts and it works great.

     This information only appears (to my knowledge) in this one
place in the Release Notes, and it was not there in Release 3.0.

     Good luck,
     Steve
-- 
Life : Stephen J. Friedl @ V-Systems, Inc/Santa Ana, CA    *Hi Mom*
CSNet: friedl%vsi.uucp at kent.edu  ARPA: friedl%vsi.uucp at uunet.uu.net
uucp : {kentvax, uunet, attmail, ihnp4!amdcad!uport}!vsi!friedl



More information about the Comp.unix.questions mailing list