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Date: Fri, 10 Nov 95 11:23:17 PST
From: troyc@sandy.merix.com (Troy Curtiss)
Message-Id: <9511101923.AA20185@sandy.merix.com>
To: ahill@netspace.net.au, freebsd-questions@freebsd.org
Subject: Re: modem lights
Sender: owner-questions@freebsd.org
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> The status signals have nothing to do with AT commands or bit mapped 
> registers - nor can they be read from RS232. For internal modems (and 
> PCMCIA I belive) they CAN be read from the BUS. (I have seen Windows and 
> MSDOS programs that do this) I have never seen a UNIX program that does 
> though. (There is one called lights.zip for DOS)
> 
> 
NO NO NO, all of this information is available not from the bus, but from the
UART that manages your serial port (Usually onboard the internal modem, 16550
compatible in USRobotics types..).  Just query the UART for the status of its
control lines...  Tear apart Seyon's code, all he does is a tcgetattr of the
serial device and run some lights with it.  I don't know if this function is
accessible if the serial device is opened by someone else, though (in the case
of implementing a system-wide modem status light watcher)...???