Mark,

As others have stated, a standard DSL modem cannot dial out.  Even if
there weren't any filters to prevent signal from the modem from leaking
into the POTS spectrum, DSL modems are not designed to be able to take a
phone line off hook.

My best guesses to the source of the problem are:
1. The FAX machine is calling out.  I would think that the FAX handshake
would be audible to the 911 operators.
2. Somebody else is using the phone line.  Somebody could have accessed
it from the Church's phone room or a cross connect box.
3. The computer hooked to the modem is using a VOIP service to make the
calls.

Three is a real long shot.  One and two are not so far fetched.  If
somebody else is using the church's phone line, you might see a number
of unusual calls that have been made, or there might be a number of 911
hangups from other phones in the same cable bundle.

-Mike

-----Original Message-----
From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf
Of Mark E. Skeels
Sent: Wednesday, August 15, 2007 6:35 AM
To: Microcontroller discussion list - Public.
Subject: Re: [EE]DSL Modem question

Heres' the nature of my question:

The local Sherriff received several 911 hangup calls from our church 
building in the last 36 hours.

The line used was the one the DSL modem is connected to. There is also a

FAX machine.

The building is empty (of people) most of the time.

We are trying to figure out how the 911 call could have been made.

Thanks,
Mark

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