Alarm Supervision Guide

By Ari Erenthal, Published May 24, 2017, 03:08am EDT

Burglar alarms can constantly monitor the health of attached circuits, sensors, and devices to ensure that they remain operational. This is known as supervision. Poor implementation of supervision is a common source of false alarms. However, if properly installed, supervision can reassure users that the alarm remains functional, and can alert installers to potential problems, allowing them to repair them. In this note, we examine alarm supervision, including

  • What is a supervised circuit?
  • Supervised vs unsupervised circuits
  • Getting the right resistance
  • Using resistors
  • Where to install the resistor
  • Insider threats
  • Implementation challenges
  • Using alarm supervision

What Is A Supervised Circuit?

A supervised alarm circuit or device is one that is constantly and actively checked by the alarm panel to ensure that it is still functional and responsive. It does this by reading the resistance on the circuit, and comparing it against a selected range. 

Alarm Supervision: Pro And Con

There are many reasons to use alarm supervision, including:

  • Some standards require supervision
  • Ability to bid on higher profit alarm jobs, such as UL listed alarms (jewelry stores, banks, etc)
  • Commercial fire alarms always require supervision
  • Ability to takeover supervised accounts
  • Supervised alarms can let alarm installer know when alarm is defective
  • If alarm is unsupervised, customer may be relying on broken alarm to protect premises

Some alarm companies never use supervision, or only use supervision for commercial applications but not residential ones. Key reasons include:

  • ****** ******* **** ********* takes ****** *** ** more *********
  • ******** ******** **** ***** ** resistors *** ********* *** must ** *******-*******
  • ************ *********** ******** ****** trained ***********
  • ** * ********* **** is *** ******** ***** away, ***** *********** *** become *****

*********** ***** ************* *** quickly ****** ************ ****** they *** ** ********* quickly *** ***********, *** highly ******* ***** ********** who ********** *** ** implement *********** ******* ****** ******** than **** *** ** not. *******, *** **** advantage ** *********** ** to ****** **** *** alarm ** ********** ********** and ******* ** ********** the ******** ** ***** it *** **** *********. For **** ******, ** is ****** *********** **** supervision ** **** ** every ****. 

Supervised ** ************ ********

** * ********** ******* opens, *** ********** **** go **** *** ********, causing *** ***** ** ** into ***** *********. *******, if *** ********** ******* goes******** ******** *** ** a *****, *** ***** goes *********** *********.

** ********, ************ ***** simply **** *** * closed *******, ***** **** alarm ********* **** ** the ******* *****.

** ********* *****, **** means **** **** *** circuit ** ************, *** panel cannot **** *** ********** between * ****** ****** and * ******* ****. *********, a clever ********* *** ******* to ***** * ****** by ******** *** **** running ** *** ******. This '******' *** ***** panel *** ****** *** adversary ** **** *** close *** ****** ******* setting *** *** *****. 

*** ********* ***** ************ how * ********** **** works.

Getting *** ***** **********

*** ********** ******** ** create * ********** ******* is ********* ** *** manufacturer. *** *******, ********* panels ******* **Ω (*,*** ohms), ***** ******** *.**Ω, and *** ******** **Ω. Because *********** ** ********* on *** ********** ***** ****** a ******** *****, ********** use * ****** ****** a******** ** ****** *** ********** is *******. * ******** ** * device **** **** * specific *** ********** ****** of ********** ** * circuit. * ******** ** a ******* ******, ***** means ** ****** ** adjusted ** ********** *** does *** *** ** output *******. **** ************* include a **** ** ********* with ***** ***** ***** sold. ********** ******** *** commonly ******* *.**Ω *** 3.2kΩ. 

*******-**** ********* **** **** long, ******** *****, ** opposed ** *******-***** *********, which *** ******** ** be ******** **** * PC *****. **** ****** alarm ********** ** **** the ******** ****** *** end ** *** *******, thus ****** *** ****** circuit * *****, ******** resistance *****. **** *** alarm ***** ***** *** circuit, ** **** **** all *** ********** *********** by *** ****, *******, and *******, **** *** resistor. 

********* **** ** ****** are ******** ** ********* (k) ** **** (Ω). For *******, * ******** that **** *,*** **** ** a ******* ** ***** as * **Ω ********. * resistor **** **** *,*** ohms ** * ******* is ***** ** * 2.2kΩ ********. 

*** ********* **** ***** bands ** **** **** they *** ***** ***. The **** ****** ****** is **** *****. *** *** colors ********** ** ******** numbers. *** ***** *** bands ******** *** ****** in ******, ***** *** then ********** ** *** third ****. *** ******* the resistor ** *** ***** has a *** ****, ******* 2, * ***** ****, meaning *, ****** ** 20, *** * *** band, ******* ** ** multiply *** ****** *****, making ** * ***Ω resistor. *** ***** **** indicates *** ********* ** the ********. **** **** is ****, ***** ********* a ********* ** ±*%. Resistors *** ******** **** in ******* *****, ***** without ******, ** ******* which ******** ** *** pack ** *** ******* one ** ****** ** know. ********* *** ** purchased from ***** ***** *** electronics ****** ******. 

Using *********

*** ***** ********** ******** for *********** ******* **** manufacturer ** ************. ***** panel ************* ******** ******* their ***** ****** **** resistors. Different ***** ************* ******* different ******** ******, ** alarm ********* **** **** a **** ** ********* alarms **** ******** ************* may **** ** **** a *** ** **** for ******* *****. 

**** ****** **** * feature ********** ********. **** ***** **** doubling, ** ********* *** run *** ***** ** wires ** * ****** set ** ********* ** the ***** *****. ** the *** ** **** pair ** ***** **** be * ********* ***** resistor. *** ***** *** identify *** **** ****** based ** *** **** ** resistance ****. 

Where ** ******* *** ********

********* ****** ****** ** ** the ***** ** *** circuit **** ** *** furthest **** *** *****. This ** ***** ***** *** ** *** line. **** ***** ***** manufacturers ***** ** ********* used **** *** ** end ** **** *********, or *****. 

*** **** ****** *********** method ******** ********** *** ******** to *** ** *** ********* of * ****** ** device. **** ** ************ effective ** ***** ** a ****** ****** ** the ****, *** ** there ** **** ****** the ****** *** * resistor. *** *******, * glassbreak ** ****** ******** can ****** *********** * resistor, *** ***** ******* are ***** ***** ** their *** ****. 

******** ******** *** ***** wired ** ****** **** other ********. *** *******, if ***** *** ******* windows **** ** **** other, ** ********* *** choose ** **** *** the ******** ********, ** that *** *** ******* share *** **** ****. In ***** *****, *** resistor **** ** ** the *** ** *** line, ***** ** ** say, *** ***** ** the **** ******** **** the *****.

**** ******* ***** ******** contacts **** ******** ****** that *** *********** * resistor. *** ******* ********, which *** ***** *** unobtrusive, ** *** **** with ******** ****** *** cannot **** * ********. Installing * ******** ** a ***** ***** ******** contact ** **** ******* can ** ***** *********** as ****. ** ********** an *** ** **** resistor **** ** *********, an ********* *** ****** to *** *** **** wire ******, ***** ****** the ******** ** ** installed ** *** ***** instead ** ** *** field (** ** *** sensor ** ******).  

******** ******** **** *****-** resistors *** **** ********* to ******** **** ******* manufacturers **** ** *** and **********. ******* ** the ********** ************ ****** from ************ ** ************, these ********* *** ***** *** stocked ** ***** ********* and **** ******* ** special *******. **** *** contact ******** **** *** panel *** **** * built-in ********. ***** **** than *** ******** ** a *******, ** ******* the ******** ** *** wrong ****, **** ******* the ***** ***** **** *********** the *******. 

Insider *******

******* ******, ** ***** nature, ******* ********** **** threats ** *** ******* of *** ********* ****. However, ** ** **** difficult ** ******* ******* threats ** *** ****** of *** ********* ****, especially ** ***** ******* can ****** *** ********* while *** ***** ** disarmed. ********* *** **** to ***** ** ****** in * ***** **** their ********* **** ****** of **** *** *********** to ***** *** ******* alarm, ******** *** **** *****, and ******** ** ******* the ***** ** **** it **** ** ****** to ****** * *****-** after *****. ***** *********** is *** *** ***** installers ****** ******* ***** insider *******.

** ** ******** ****** a **** ** "*****" a ******* ****** *** day, ********* ** **** back *** ****** *** place ** *****, *** alarm **** **** * trouble ****** ** *** keypad, ****** * *********** party *** *********** ** investigate *** ***** *** source ** *** *******.

Implementation **********

*********** **** ** ***** step ** ****** ******, and ********* *** ** tricky ** **** ****. It ** ***** ********* to *** ********* ** low ******* ******** ******** and ***** ***** ********. Magnetic ******** **** ***** in ********* *** *********, but **** *** **** expensive **** ******** ********. However, *** ******* ********* is *********** *****, *******, the *** ** *** line ******** **, ********** when ****** **** *****. *********** the ******** ***** ******** either *********** ***** ****** or ********* ********** **** a ***** ***** *** fact.  

*** **** ****** ****** of ********* ** *** exact ********* ** *** resistor. ********* **** ** placed ** *** ******** point ** *** ****, which ** ** *** device. ** **** ** placed ****** *** ********, not ****. ** * resistor ** ****** ****** *** end ** *** ****, anything ******* **** **** be ************, *** ** a ******** ** ****** across *** ********* ** the **** ******, ** will ******* *** **** from *******.

 

Comments (13)

The picture on the right is mistakenly labeled 'incorrect'. If this is an "Open Circuit device" such as Foot pedal, Money clip, etc. it is in the right place. Secondly, not often but it has happened,  manufacturers will label a device as to the condition of the relay when activated, therefore this is correct as well.

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Yes, that would be true if it were an NO device, but it's actually an NC device. 

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Most modern powered detection devices with "NC" and "C" are closed loop (or Normally Closed), so in that case it would be incorrect.

 

The picture with same device where resistor is properly placed, I would have incorporated the tamper:

green on 1st "T", one leg of resister on 2nd "T", other leg of resistor on "C" and white on "NC"

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Great point! But I actually wanted to address tampers in a separate guide. 

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Here we often use double end of line (DEOL) to allow for both alarm & tamper conditions on a single pair. It allows tamper monitoring 24/7 for both sensor housing & cable tamper along with alarm monitoring only when system is armed

 

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Another great article, Ari!

You have touched upon one of pet gripes: the failure of installers to place EOL resistors where they belong - at the end of the line. I just completed a survey of 32 commercial sites that had intrusion alarm systems installed by a variety of alarm companies. In nearly every case, the resistors were at the panel. The exception was a multiplexed system that used zone expanders out in the field. In this case, the resistors were at the zone expander, not at the device. Same problem.

I consider this practice to be negligence on the part of the installer. In jobs we specify, we always verify that EOL resistors are properly installed and will make the installer rework the job if it isn't right.

Looking for your article on tamper switches, another one of my pet peeves. I did a short article on the topic myself a short time back.

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In jobs we specify, we always verify that EOL resistors are properly installed and will make the installer rework the job if it isn't right.

Michael, do you explicitly call this out in the RFP itself? I am curious what level of detail you include.

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Within each RFP,  I have a specification section called "Basic Materials and Methods" that includes detailed requirements for conduit, cabling, fasteners, and installation techniques.

The paragraph that addresses EOL resistors typically reads something like this:  

"Install end-of-line resistors at each detection device as per manufacturer.'s installation instructions. End-of-line resistors shall be connected to flexible wire leads and protected with heat-shrink tubing or equivalent. End-of-line resistors shall be installed at the final connection point nearest to the device unless specifically noted otherwise. End-of-line resistors shall not be installed at the control panel, input board, or zone expansion module."

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Well, I guess you can't do it right if you were never shown the right way to do it. 

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Poor training is often an issue, but I also expect installers to take the time to fully read the installation and programming manuals for the equipment they are installing. 

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Good eye. I needed that resistor for another device, so I couldn't use a permanent splicing method. I realized my mistake when I tried to take the resistor off my magnetic contact. In the old days, you could just run to Radio Shack and buy a fistful of resistors for a couple of bucks, but not anymore. 

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