From: stevef@wrq.com (Steve Forrette)
Newsgroups: comp.dcom.telecom
Subject: Re: Advice Needed on Telephone Security Systems
Date: 9 Nov 92 22:20:28 GMT
Organization: Walker Richer & Quinn, Inc., Seattle, WA
X-Submissions-To: telecom@eecs.nwu.edu
X-Administrivia-To: telecom-request@eecs.nwu.edu
X-Telecom-Digest: Volume 12, Issue 834, Message 2 of 11

In article <telecom12.829.3@eecs.nwu.edu> khx@se44.wg2.waii.com
writes:

> Most houses hit have the breakers outside the security zone. Crooks
> snip the phone lines and cut the power off. If someone's home, the
> owner goes out to turn the power on and the alarm off. (S)he then
> walks back in with the crooks. If they are not home for (say for the
> weekend) crooks come back after 24 hour when the battery back up is
> drained for the siren. The alarm monitoring company is NOT notified
> since the phones are dead and that's the only lifeline back.

Ademco is a manufacturer of alarm system equipment that makes a line
of wireless alarm monitoring equipment to supplement the regular
dialup alarm systems.  Other manufacturers may make similar equipment,
but I don't know.  Here's what I know about the Ademco system:

An alarm monitoring company in your area must have the base station
transmitters for the system.  You then subscribe to the radio
monitoring in addition to the regular monitoring with the same
company.  They install one of two types of radio systems to your
current alarm system.  There is a one-way system and a two-way system.
The one-way system sends an immediate signal upon an alarm condition,
and a "keep-alive" signal every minute or so.  If a house was hit as
you describe above and the alarm was triggered, the alarm company
would know right away.  The radio unit usually is hooked up to the
bell output of the alarm, so when the alarm company gets the radio
signal, they don't have detailed information such as which zone, etc.,
was triggered.  

Under normal situations, the regular landline dialup mechanism will
deliver this information in the normal manner shortly after the radio
signal is received.  If the radio alarm is not followed by a landline
dialup, this is a good indication to the alarm company that the line
was cut.  Also, the phone line is usually connected to the radio unit
as well.  If the phone line goes dead (such as it would if cut), the
radio unit signals this event immediately to the alarm company.  Power
outages can be signaled, but are not usually done so because of the
number of false alarms this would cause.  Imagine how many systems
would try to dial up if there was a regional power outage.  But in
your case, the alarm company would know immediately that the phone
line was cut, and with the company I've dealt with, this would result
in an immediate police dispatch for investigation.  If this was
followed by an actual alarm condition, this would be further
indication that all was not well at the ranch.  If the alarm and radio
unit is totally disabled, the alarm company still knows of this within
a few minutes when it does not receive the keep-alive transmissions.

The two-way unit is similar, but can also receive messages from the
alarm company.  Instead of sending periodic keep-alive messages, it
responds to polls from the alarm company base station.  If your unit
does not respond to a poll, then the alarm company knows something is
wrong.  As with the one-way unit, phone line cuts and alarm conditions
are transmitted immediately.  Both of these systems are capable of
using multiple frequencies for redundancy.  In the case I'm familiar
with, the alarm company maintained several base stations throughout
the area, with the goal that at least two or three are within range of
every customer.  This way, if one of the base stations stops working,
each subscriber's radio will switch over to one of the other
transmitters on a different frequency.

I'm sure Ademco could give you a reference to an alarm company in your
area that offers this service.  As far as I could tell, there was no
way for someone to defeat the system by just cutting wires, etc.  Even
cutting the antenna to the radio simultaneously with the power and
phone will not defeat it, as the silence from your residence will
alert the alarm company to trouble within a couple of minutes.  Plus,
it would be really difficult to get to the radio unit simultaneously
with the power and phone, without triggering an alarm condition a few
seconds prior in the process.


Steve Forrette, stevef@wrq.com