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Tech Tips ‘n Tricks (of the Trade):

Basic Communications!

“I haven't spoken to my wife in years.
I didn't want to interrupt her!”

-- Rodney Dangerfield

First, a brief word about Digital Telephone Service. In Canada, this is being provided (primarily) by Shaw Communications, Primus, or Rogers Cable. The modem usually supplied for interface to the television cable jack has a very small back-up battery inside. Typically this is only good for four (4) hours of standby time. In our view, this is an unacceptable connection for any fire alarm communicator employing a normal telephone line as the primary means of signal transmission (not to mention that it DOESN’T meet the requirements of CAN/ULC-S561). 

Some AHJ's have accepted this type of connection as long as a UPS (Uninterruptible Power Supply) of sufficient standby capacity to meet the "twenty-four hour rule" is supplied. We would suggest that such a "workaround" should only be acceptable if the UPS were monitored by the fire alarm system for "trouble" conditions (like "low battery" or "fuse failure”). 

It should be noted that even the basic UPS (as long as it could successfully demonstrate compliance with the twenty-four hour rule) would tend to meet the requirements presently proposed in the latest edition of CAN/ULC-S561. 

VOIP has another frequent problem.  Providers (like Shaw) usually tend to perform routine maintenance on their infrastructure in the “wee hours” of the morning.  This means the system will go down usually around the same time when the twenty-four hour test signal is transmitted.  If the system fails to communicate the test, it will go into local trouble (which would trigger the back-up communicator).  You really don’t want a customer called at 3:00 AM just because the VOIP provider has temporarily interrupted service!

For the purposes of this "TIP", we are assuming a normal "POTS" line as supplied by Telus (or Bell in Canada) is utilized.

Fire alarm communicators come in a variety of "flavours". Let's start by identifying each one and then discussing their pro’s and con’s:

Dual line digital communicators are the "vanilla" in our counter. There are several manufacturers and a number of "approved" models, although many jurisdictions no longer find them an acceptable means of transmitting fire alarm signals and ULC has "delisted" many. Those still in service are "grandfathered" for the most part, but check with the local AHJ to make sure.

Communication method used: Normal POTS telephone line. Special Note: Use of VOIP or other enhanced telephony technology may actually prevent older versions of these units from dialing.

Back-up method: Normal POTS telephone line (hence the term "dual line" communicator).

Transmitter test: A communicator test signal must be generated by the system every twenty-four (24) hours. You must determine the time of the signal and ensure that the daily test regimen is being followed. How do you do this? Contact the central monitoring facility and verify with the operator that the system is transmitting the required signal.

Pros: Cost effective

Cons: NFPA 72 stipulates that the primary and secondary communication lines be terminated in separate trunks at opposite ends of the protected premises. Most telephone companies provide a single "drop" and usually from a common feed (on a pole or termination box). This means that both lines could be easily compromised. In many instances, building owners will often "forget" what the extra phone bill is for and cancel one (or both) of the lines. It's important to review the daily test reports generated by the monitoring station to ensure the unit is communicating properly. A "fail to test" report is usually indicative of a telephone line problem.

Manufacturers: Silent Knight, Digital Security Controls (DSC), Ademco, Contronics, FireLIte, Notifier, Mircom, Paradox, Potter

DVACs communicators are still the "cream" on the Sundae. They are widely accepted as a "top tier" method of transmitting fire alarm signals.

Communication method used: Dedicated addressable transponders that are polled for status every few seconds by special central station receivers. Signals are transmitted via a network of dedicated data lines that are routed through hardened, secure "hubs" directly to the central monitoring facility.

Back-up method: None. Failure of a unit is immediately identified at the central monitoring facility and will result in an immediate pre-determined response.

Transmitter test: This unit is online as part of a dedicated network. Disconnection will cause a "line fault" condition to register at the central monitoring station.

Pros: Secure, stable, solid

Cons: Expensive. Monitoring agencies will usually take responsibility for the line charges from the telephone provider. These are "added" (often marked up as well) to the cost of the actual monitoring service.

Manufacturers: Europlex, SureGard, Contronics, Morse, Chubb, ADT

Long Range Radio (LRR) communicators are "truffles". This technology requires a significant infrastructure investment on the part of the monitoring agency. "Repeater" stations must be utilized to provide coverage beyond the (usually) ten (10) mile transmitter range.

Communication method used: As to be expected, this is a wireless communication method utilizing radio frequency (RF). There is minimal reliance on cabling (except to power the unit).

Back-up method: None. Failure of a unit in the network is immediately identified.

Transmitter test: This unit is online as part of a dedicated network. Disconnection will cause a "line fault" condition to register at the central monitoring station.

Pros: Secure, stable

Cons: Expensive. Requires the monitoring agency to invest heavily in receiver technology which is proprietary to one manufacturer (in other words you can't have transmitters from two separate manufacturers "talking" to one receiver). This cost, of course is "passed on" to the end user.

Manufacturers: Ademco (Honeywell), Morse

GSM communicators are the chocolate. The transmitters are have become extremely versatile.  They can serve as either a “passive” backup to a standard POTS line or can be programmed to send “pings” every 90 seconds to a central station receiver (which makes it an “active” communicator).   It can be installed as part of a stand-alone fire alarm alarm communicator or it can be “paired” with a DACT (on-board fire alarm system communicator).

Communication method used:  Existing cellular networks.  This is also RF technology similar to Long Range Radio with a "wired" component.  The signals generated by the transmitter are received at the manufacturer's receiving centre which then re-routes it to a normal telephone line and the central monitoring stations digital line receiver.

Back-up method: None. GSM is usually the "backup" for a single line digital communicator.  When programmed as an “active” communicator, failure of the unit is identified almost immediately at the monitoring station.

Transmitter test: When in “passive” mode, a communicator test signal must be generated by the system every twenty-four (24) hours. Follow the procedure for a dual line digital communicator.

Pros: Stable

Cons: As with any compromise, heavy reliance is placed on cellular network technology.  If programmed as a “passive” system, the failure of the unit could be transmitted by normal phone line (as long as this is also not compromised). Otherwise, the central monitoring facility will usually alert the alarm provider when the daily "test" signal is not received.

Manufacturers: Tellular, DSC, DLinks, Honeywell

IP communicators are the "mousse". The transmitters are part of the family of "active communicators", and are often sold as an option module by several digital communicator manufacturers.

Communication method used: This utilizes a network connection via an on-premises LAN switch or router connected to the internet via either a cable or DSL or ADSL modem. Communication is via pulsed "packets" to a dedicated receiver located at the central monitoring facility which has a similar WAN connection.

Back-up method: None. IP communicators are usually the "backup" for a single line digital communicator.

Transmitter test: The unit is an "active communicator". Disconnection will cause a "trouble" condition to appear at both the protected premises and the monitoring station.

Pros: Stable (but heavily dependent on the reliability of the Internet Provider)

Cons: Heavy reliance is placed on the cable or telephone provider's Internet connection. Less secure than LRR or DVACs. Failure of the unit could be transmitted by normal phone line (as long as this is also not compromised). Failure of the local network connection or modem will also result in a loss of signal. Because most providers perform regular maintenance of their infrastructure in the early morning hours, this results in frequent "trouble" signals. The central monitoring facility will usually alert the customer when a trouble signal is received.

Manufacturers: DSC, Honeywell, Elk



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Alarm communicators utilize a number of methods in which to connect to your fire alarm panel. Mircom, Potter, Notifer and FireLite all manufacture digital "UDACT" communicators that are either integral to their particular common control board or connected to them by a ribbon cable (I should mention that, in the latter instance, for the communicator to work properly, it must be "paired" with that manufacturer's common control). The advantage here is that individual zones can transmit signals so that the central monitoring station can actually identify the location of the fire and relay this to the responding authority. After-market communicators must utilize the common alarm, supervisory and trouble contacts on the fire alarm panel and can only transmit "generalized" alarm, supervisory, and trouble signals. Regardless of the method of connection, you (as the testing technician) must be able to recognize whether this has been accomplished correctly.

In the case of an optional UDACT communicator, the unit is usually mounted on special rails or stand-offs supplied by the manufacturer for the purpose and located inside the fire alarm panel. The fire alarm installation manual will illustrate the connection method and provide you with the necessary details to properly test the unit. In all instances involving UDACT units, there will be two telephone lines terminated to the unit. This is normally done through twin eight position jacks which should be located immediately adjacent to it. Disconnection of one (or both) jacks will cause the fire alarm system trouble buzzer to sound. If one jack remains connected the UDACT will transmit a "line fault" trouble to the central monitoring facility.

All other communicators are housed in metal cans mounted adjacent to the fire alarm system and will employ pre-programmed zones similar to those of the fire alarm panels initiating circuits. End of line resistors must be connected across the normally open relay contacts in the fire alarm control panel. The wire/cable between the communicator and fire alarm system must be physically protected usually via flexible conduit (BX) or EMT. The communicators must employ tamper switches on the access cover, a visual method of identifying whether AC power is present and if a trouble condition exists. The Silent Knight 5104 provides all these through a viewable "window" on the front cover, but I have seldom seen the proper cover tamper used (needless to say, this would constitute a deficiency!). DSC, Ademco, and other "stand alone" units utilize an AC "on" LED that is normally installed in one of the knockouts and a separate keypad that will display the zoning information and any system troubles. If the keypad is missing, then there's no way to determine the status of the communicator. I've even seen some alarm companies install the keypads inside the can (which means you have to open it to see the status). Needless to say, neither of these installations would pass.

TIP: A "low battery" signal received by the central monitoring facility does not automatically translate to a "low battery" on the fire alarm system. It will usually mean a "low battery" condition exists in the communicator and the servicing agency (or the monitoring company) must be notified.

Power to the communicator must be provided via a dedicated circuit (similar to the one used by the fire alarm system). In the case of a UDACT, power for the unit is provided by the fire alarm’s AUX power output (which is often supervised).

Let's review the communicator section of the standard annual test report we provide in our Forms section. This is now on a separate page called “C2.11 Interconnection to the Fire Signal Receiving Centre”. 

A.  The fire signal receiving centre transmitter is integral to the fire alarm control unit.  This is pretty well self explanatory. Is the communicator a UDACT or not?

B.  the fire signal receiving centre transmitter is located remotely from the fire alarm control unit.  Is it a stand-alone communicator?

C.  Tested and confirmed operation of the alarm relay.
D.  Tested and confirmed operation of the trouble relay.
E.  Tested and confirmed operation of the supervisory relay.
  In a stand-alone system (or one which might utilize a connection to a GSM-Cellular or separate IP communicator), you have to ensure that the fire alarm system’s on-board relays actuate to transmit the appropriate signal to the central station.  On some smaller systems that don’t employ a supervisory relay, simply check the box marked “N/A” for item “E”.

F.  Confirm that the alarm transmission to the fire signal receiving centre is received.  Self-explanatory.

G.  Confirm that the supervisory transmission to the fire signal receiving centre is received.  Self-explanatory.

H.  Confirm that the trouble transmission to the fire signal receiving centre is received.  Self-explanatory.

NOTE:  Items F, G, and H require you to actually contact the monitoring station to verify the signals received.  You must check that all signals generated by the fire alarm system during your test are received by the monitoring station. In many instances, burglar alarm companies install these units and some employ a little known programming dongle called swinger shutdown.  What this means is that the communicator limits the number of alarm events it transmits on a specific zone in a given period (usually 24 hours).  For instance, if your fire alarm system is transmitting alarm signals on "zone 1" of the communicator, swinger shutdown may be enabled after as few as three alarm events in a twenty-four hour period.  It is important that "swinger shutdown" is DISABLED on a fire alarm communicator.  I don't think I need to paint you a picture as to the reason why!

I.  Operation of the fire signal receiving centre transmitter bypass means results in a specific trouble indication at the fire alarm control unit or transponder.  This is often a button (or switch) on the common fire alarm control marked “auxilliary disconnect” or “central tie” which, when activated, will bypass the alarm relay and prevents the communicator from transmitting alarm events.

J.  Operation of the fire signal receiving centre disconnect means transmits a trouble signal to the fire signal receiving centre.  This means that a trouble event will be transmitted to the monitoring station.

K.  Record the name and telephone number of the fire signal receiving centre.  Self-explanatory.


We’ve added some additional checklist items to this section which, while not actually mandated by the Testing Standard, will provide some helpful information to the guys driving the bright red (in some cases yellow) trucks, if you are confident enough to fill them out.

Communicator is installed in accordance with CAN/ULC-S561.  This actually requires some special knowledge to complete.  You’ll have to be able to verify that the communicator being employed has a current ULC Listing (some as I have mentioned have been DELISTED).   You must also determine that the unit has been installed correctly.  The checklist for this includes (but is not limited to):

  • Dedicated circuit disconnecting means (breaker) for the communicator;
  • All interconnecting wiring must be installed in rigid EMT conduit or armoured "BX";
  • A visual means to identify "trouble", "supervisory" and "alarm" signals locally (through either a keypad or similar display located adjacent to the communicator's enclosure);
  • An AC power "on" indicator;
  • A tamper switch for the unit's common control cover/door/lid;
  • Standby power supply of sufficient size to supervise the fire alarm system for the required time mandated by Code.

If you check “NO” here, you’ll have to explain what exactly it is that isn’t compliant in either the “Deficiencies” or the “Comments” sections of the form.

The fire signal receiving centre is ULC Listed.  In order to check “Yes”, you’ll have to see if the monitoring station has the “Fire Protective Signalling systems, Signal Receiving Centres, Full and Shared Service” Listing by entering their name in the ULC directory search form.

The fire signal receiving centre ULC certification number is?  This number is located on the search results page you will have viewed from the previous item.  The centre’s ULC certification is typically be predicated by the letters DAYIC followed by a set of numbers.  Write down the whole number.

Communicator is being tested in accordance with CAN/ULC-S561.
Supporting documentation attesting to this is on site and has been reviewed.
  CAN/ULC-S561-13 now mandates completion of its own Appendix “C” test form, a copy of which must be maintained on the premises.  If you don’t have access to the report, you can (should) request a copy for your records.  The next line item is extremely important!

The ULC “Central Station Fire Protective Signalling Service” Certificate is Valid.  If provided, both types of ULC Certificates mentioned in the previous item have a small table which the servicing agency is required to fill out for every year that the Certificate is valid.  A sample of the Certificate is provided below.  Also check to make sure that the date of issue and the expiry year fall within the dates that you are performing the testing!

The ULC “Central Station Fire Protective Signalling Service” Certificate expires on:  If applicable, fill in the expiry date on the Certificate.

The last inspection noted on the Certificate occurred on:  If applicable, fill in the last date on the table mentioned above.

The communicator has been reset following completion of testing.  Some of the DSC and Ademco transmitters require you to enter an “off” sequence (or reset code) to trigger the internal relay connection to the secondary transmission means.  When you’re talking to the nice people at the monitoring station to verify the transmission of all the signals, inquire about the system being fully “restored” after you’ve completed your testing.  If they state they still show an “unrestored alarm” event, try “resetting” the communicator.  Instructions to do so will usually be on the keypad (and usually require the entry of a simple code like “1”, “2”, “3”, “4”).

The communicator has been placed back into service.  When you’ve completed your testing, don’t forget to relay that fact to the nice people at the monitoring centre.

The communicator is trouble free.  This means no “yellow” lights or intermittent beeping from the communicator or UDACT!

In Vancouver you’re also required to ensure that the monitoring station is on the City’s “approved” list.  This may take a little "digging" (monitoring stations are often reluctant to divulge such information), but a really handy source is provided by the City of Vancouver here.

SPECIAL NOTE! In Vancouver (and many other jurisdictions across Canada), regulators may have interpreted the Building Code Section (2) to mean that the actuation of a sprinkler system or linked suppression system must also initiate a separate “waterflow” signal to the monitoring station.  In our view, this is an excellent provision as it clearly indicates to First Responders that the sprinkler system has been tripped.  Some older fire alarm panels are incapable of producing more than a "common alarm" and a "common trouble" output, however, on newer units a dedicated relay which “follows” the sprinkler/suppression system initiating zones should have been  installed.

Congratulations! You've just received a "crash course" in alarm communicators.


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