Re: another newbie, what to do with this Brinks alarm system?

[t@xxxxxxxxx (Todd H.)]

G. Morgan <alarmpro@xxxxxxxxxxx> writes:

> On 03 Nov 2006 16:08:46 -0600, t@xxxxxxxxx (Todd H.) wrote:
>
> >"Crash Gordon" <webmaster@xxxxxxxxxxxxxxxxxxxxx> writes:
> >
> >> Basically you throw out the alarm panel and the keypads and buy something
> >> else you can install your self. Everything else should be reusable although
> >> you might have to look for buried resistors if they put them at the end of
> >> the line and remove them.
> >
> >Cool--this is sort of what I envisioned.   I did see in the alarm
> >panel a small pack of resistors just kinda sitting there hanging -- as
> >though it was something they used as piece parts for whatever reason.
> >
> >When you say end of the line, you mean on the sensor end of the line?
> >And at the risk of asking what may be a FAQ, what purpose do these
> >resistors serve to the Brinks system?  (I'm new to the security system
> >hacking realm, but have a strong background in electronics, for
> >whatever that's worth).
> >
>
>
> EOLR's are used to supervise the alarm loop.  With a preset resistance
> on the loop the panel is monitoring the current in the circuit, now it
> can detect open, close, and partial short -- as well as tampering with
> the circuit between the control and device.

Ahhh.  Gotcha.  A third logic state if you will.  Makes a lot of
sense.

> Most residential installers disable EOL supervision in programming and
> just go for a open/close, that or put the EOLR in the panel which
> completely negates the whole purpose of the EOLR in the first place.

Oy.   Oh man.

> Think about knocking out a brick under a window and putting hemostats
> on the wire, BEFORE it reaches the contact and you'll see why EOLR's
> are useful.

Absolutely.   Easy way to disable the sensor.

Thanks for the education.

--
Todd H.
http://www.toddh.net/