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List:       firewalls-gc
Subject:    Re: [Fwd: Internal modems ?]
From:       "Patrick O'Callaghan" <poc () usb ! ve>
Date:       1997-01-30 8:09:40
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Patrick Larkin Jr writes:
>Pierre-Yves Bonnetain wrote:
>Well, *I* used to run a "war-dialer" over all our DID numbers
>that were NOT known faxes/modems.  Now, we have a Northern 
>Telecom with mostly digital lines, so modems can't easily 
>be attached.  What I REALLY want is some software that sits
>in the PBX, "listens" to calls enough to detect if there's
>a modem talking on a line that should be voice only.... then
>tear down the call if there is.  I've heard of such a thing,
>but NorTel is clueless.  Anyone know of such a package?

Random thought: would it be possible to insert a (hardware) filter
on incoming lines to block modem signalling frequencies? This would
not disturb voice traffic but might be an effective solution. Modern modems
of course use a whole spectrum of frequencies in parallel, but all you
would need is to prevent the initial protocol negotiation, which is
much more fixed.

Or am I totally clueless?

Patrick (Not At All A Hardware Expert) O'Callaghan
-- 
Prof. P. O'Callaghan			Internet: poc@usb.ve
Departamento de Computacion		NICNAME: PO22
Universidad Simon Bolivar 		Tel: +58 (2) 906-{3241,3242,3254}
Caracas, Venezuela			FAX: +58 (2) 906-3243
(Ask for my full postal address)	"Errare uHmanum Est"

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