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From: wls@garden-brau.csd.uwm.edu (Bill Stapleton)
Newsgroups: comp.unix.wizards,comp.unix.internals
Subject: Re: Getting status of DCE device from a DTE device
Message-ID: <11590@uwm.edu>
Date: 30 Apr 91 15:34:03 GMT
References: <8283@alpha.cam.nist.gov> <1991Apr29.211345.12615@chinet.chi.il.us>
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In article <1991Apr29.211345.12615@chinet.chi.il.us>, les@chinet.chi.il.us (Leslie Mikesell) writes:
> In article <8283@alpha.cam.nist.gov> coleman@cam.nist.gov (Sean Sheridan Coleman X5672) writes:
...
> >I am trying to make sure that the port plugged into the 
> >back of my Sparc Station is hooked into something.
...
> To test for carrier detect being asserted, all you have to do is
> set a short alarm and attempt an open.  If the alarm hits before
> the open completes, you were blocked waiting for CD.  Or, with
> Suns you can open with O_NDELAY and use their ioctl() extensions
> to retreive the modem status.

This is probably obvious to all you experienced SUN people, but make sure
you don't have the "soft carrier" stuff turned on.  I helped hook a printer
up to a new Sparc Station, and as shipped, the soft carrier for the tty port
was locked on - So stuff would "print" whether the printer was on or off or
unplugged or ...

--
Bill Stapleton
     wls@csd4.csd.uwm.edu
     uwmcsd4!wls