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Date: Thu, 13 Apr 1995 11:24:22 +1000
From: Bruce Evans <bde@zeta.org.au>
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To: davidg@Root.COM, nate@trout.sri.MT.net, phk@ref.tfs.com
Subject: Re: cvs commit: src/sys/i386/isa sio.c
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>>> > A magic sequence of chars would be a misfeature, as it would be for
>>> > syscons.  The escape should be out of bounds (perhaps it should optionally
>>> > be break && some combination of the modem status lines).
>>> 
>>> No, we want something you can send on a modem...

>   Excuse me, but why do you think you can't send a break over a modem (you
>certainly *can*)?

You can't send `break && boolean_function_of(DCD, DSR, CTS)' over a modem
in a controlled way.  At best you can hang up and have a modem that can be
and is programmed to drop DCD and maybe DSR and CTS.  Break should certainly
not cause entry to the debugger if DCD is low (and CLOCAL is clear :-).  I'm
not sure if break can be guaranteed not to occur before DCD goes low upon
hangup or turning off of a terminal.

Bruce