[net.general] Call waiting for dial-in users

draper (01/18/83)

Mark Wallen and I here at UCSD have finally got our modems and software
here to support call waiting.  "Call waiting" is a feature for $3.00 a
month the phone company sells me whereby if I am on the phone and someone
else calls, I get a beep and can then put my first call on hold while I
talk to the second.  My aim is to get this to work so that I don't need to
buy a second phone line, yet if friends call me when I'm logged in for
hours I can detect this and talk to them. 

The problem was that formerly the computer hung up when I put it on hold
because the carrier dropped.  Now we have fixed it so that it hangs in
there until I get back to it.  Other people dialling in will not get
connected to my job -- it's still connected to my phone line.  When I log
out, then the modem hangs up the phone and the line is ready for use again.
The only problem is that if anyone using this feature does not logout
before hanging up, the line is left busy and no-one can use it (their job
will hang around in the machine as well).  To fix this we have a daemon to
kill jobs automatically on dialin lines that have been idle for more than
say 30 min.s without carrier. 

The only remaining problem with call waiting on computer lines is that the
beep appears as only 2 char.s of noise on the screen typically, which can
be hard to spot, and will be missed if you've wandered off and aren't
actually looking at the screen.

We are posting a companion note to net.unix-wizards on what your local wizard
should do to get this working on your machine, and the source for the daemon
to net.sources.

Mark Wallen		  	 Steve Draper
UCSD, San Diego			 UCSD, San Diego
ucbvax!sdcsvax!sdcsla!wallen	 ucbvax!sdcsvax!sdcsla!draper
wallen@nprdc			 draper@nprdc