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Path: utzoo!utgpu!attcan!uunet!husc6!cs.utexas.edu!vixen!ronbo
From: ronbo@vixen.uucp (Ron Hitchens)
Newsgroups: comp.periphs,comp.unix.questions,comp.dcom.lans,comp.unix.wizards
Subject: Re: !!! HELP !!! Problem with UNIX tip (cu) and modem
Message-ID: <248@vixen.uucp>
Date: 4 Aug 88 18:55:23 GMT
References: <296@mrsvr.UUCP>
Reply-To: ronbo@vixen.UUCP (Ron Hitchens)
Organization: My House, Austin TX
Lines: 53

In article <296@mrsvr.UUCP> ssa@mrsvr.UUCP (xxxx) writes:
>
>	I have a MultiTech 224E modem connected to a Sun 3/50 ttya port.
>	I have it set up so it will answer on the third ring, and
>	saved this configuration in the non-volitile ram.  The problem
>	is every time I dial a number using tip (or cu) the modem 
>	resets it self to factory configuration, unless I turn it off
>	and on (giving it the ATZ command also works). This is a pain in the 
>	neck because I am using my office phone, and if I forget to reset 
>	the modem it picks up the phone immidiately, therefore greeting the 
>	caller with a high pitch tone! 
>
>	My question is:	is there a way to tell the modem to reset itself
>	(ie: give it the ATZ command) after the dialing, and also:
>	what makes the modem go back to factory configuration?
>
>	Thanks,   ssa

   Yes, that's easy to fix.  Actually, tip is not setting the modem to
the factory defaults, it's sending down a string to explicitly set certain
values.  Both tip and uucp (they share the same dialing modules) contain
this string, which is part of the Hayes dialing code:

	ATV0Q0E0S0=1S2=255S12=255

   This sets: Not Verbose, Not Quiet, No Echo, Register S0 to 1,
Register S2 to 255 and Register S12 to 255.

   Modem registers S2 and S12 control the modem escape sequence, setting
them both to 255 effectively disables it, allowing the modem to pass
arbitrary binary data.  The setting of register S0 is where your problem
lies, this register indicates which ring to answer the phone on (setting
it to zero will disable answering).

   So, the solution is very simple, all you need to do is to patch this
string in the tip binary from:

	ATV0Q0E0S0=1S2=255S12=255
to:
	ATV0Q0E0S0=3S2=255S12=255
		   ^

   You'll need some sort of binary editor, I use something called bpatch
which I got from the net.  Or, if you have sources you can modify the
source file and recompile.  In either case, be sure to maintain the proper
permissions on /usr/bin/tip when you're finished (patching will probably
reset the setuid bit) so that tip can create and removing the lock files:

-rws--x--x  2 uucp     daemon      98304 Sep 15  1986 /usr/bin/tip

   Hope that sheds some light.

Ron Hitchens		ronbo@vixen.uucp	hitchens@cs.utexas.edu