Need help with modems under Ultrix

Frederick M. Avolio avolio at decuac.DEC.COM
Fri Aug 8 00:50:43 AEST 1986


[ I have written to him about this, but thought that others might have
the same questions... ]

In article <3097 at ncsu.UUCP>, mark at ncsu.UUCP (Mark Lanzo) writes:
> The problem:
>     Nothing I or anyone at our site has been able to do has worked to
> convince the system to handle the line properly.  We had no problems 
> before when we were running under V1.1 of the OS, but apparently V1.2
> handles terminals in a significantly different fashion.

Yes indeed.  Assuming the /etc/ttys file is set up correctly (and you
should check this) you still need to tell the operating system to use
modem control on the individual line(s) through the flag field in the
config file for the system.

> The problems we have are (a) baud-rate switching does not seem to work
> very well for dial-in users, (b) system tends not to know if the phone line
> has been disconnected, and hence doesn't log you off if you hang up or get
> cut off.

 a) sounds like a modem problem (the system shouldn't have any control
over this, although make sure the entry in /etc/ttys properly rotors
on the speeds you want (You probably want d1200 on the line such as...

ttyd1   "/etc/getty d1200" dialup       on modem shared


>    Dial-in use:
>    ...
>    As already mentioned, if you DO get on, and get disconnected, the system
>    won't log you off.  Definitely a security problem!

The latter would be caused by not telling the system of modem control
in the config file.

>    Dial-out use:
>        Actually, dial out use has been fairly well behaved.  I've written 
>    programs which stop/start the getty on the line, then connect you to
>    the modem (via C-Kermit).  Here I would just like to know if anyone has
>    a GOOD system for doing this, or a better approach.  

Yes, Ultrix does :-).  Tell it you want to set up the line as shared
(see ttys line example above).  This'll turn it on and off correctly.
See the release notes regading this for a caveat or two.

Finally, perhaps the switches (software registers?) on the hayes are
incorrectly set.  I received the following, which may be of help.
Note, that is is for hoking up to a dmf-32.

->   The following is what we found to be a viable solution as far as using 
-> Hayes 2400 baud smartmodems with a DMF-32. ...
-> Use appendix of the Smartmodem 2400 User's Guide, and the switch settings 
-> recommended for use with the Hayes 1200 baud modem. These commands will
-> set up the modem to talk to the DMF-32 and do auto answer.
-> 
-> Switch setting Hayes 1200	function	smartmodem 2400 command
-> switch 1 up			Dtr status	AT&D2&W
-> switch 2 up			Result code mode ATV1&W
-> switch 3 down                   Result code disp ATQ&W
-> switch 4 down                   Command echo    ATE&W
-> switch 5 up* not in etc/remote	auto answer     ATS0=1&W
-> switch 6 up			detect carrier	AT&C1&S1&W
-> switch 7 up			telephone jack  AT&J&W
-> switch 8 down                   command recog   see dumb mode strap
-> switch 9 up                     bell/CCITT      ATB1&W
-> switch 10 up                    modem reset     AT&D1&W

-- 
Fred @ DEC Ultrix Applications Center
INET: avolio at decuac.DEC.COM				* Fight the Fight *
UUCP: {decvax,seismo,cbosgd}!decuac!avolio	       * Rescue the Unborn *



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