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From: ropg@ooc.uva.nl (Rop Gonggrijp)
Newsgroups: comp.dcom.telecom
Subject: Re: Keeping a Line "Busy" Without a Phone Off Hook
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Date: 26 Nov 90 19:00:21 GMT
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DAN@gacvx2.gac.edu (Dan Boehlke) writes:

>What is the best way to busy a phone line?  I have a bank of modems
>and from time to time I need to pull one from the pool.  Some modems
>have a "busy out" swtich.  My modems do not have a switch.  Pulling a
>modem causes the hunt to stop at modem I pulled, giving the caller a
>"no one is home" type ring.  I have heard that putting a resistor
>accross the wire is enough to hold it off hook.  

It's even simpler: just short the phone wires (tip and ring) and
presto.

>If memory serves it was a 1000ohm resistor.  I have hesitated to do
>this without trying to learn more.  What effect does this have on the
>switch?  Does the effect varry from phone switch to phone switch?

1000 ohms definitely sounds too high. If you insist on using a
resistor, use 10 ohms instead. The switch itself limits the current to
about 20-50 mA so there should be no problem. Always play with toys
they tell you not to play with..... ;*)


Rop Gonggrijp (ropg@ooc.uva.nl) is also editor of  Hack-Tic (hack/phreak mag.)
Postbus 22953    (in DUTCH)   1100 DL  AMSTERDAM   tel: +31 20 6001480