Difference Between Active and Passive Alarm Monitoring

The role of an alarm monitoring panel is to communicate the signals produced by your fire alarm or intrusion alarm panels to a Signals Receiving Centre (SRC).  In order to achieve this, the monitoring company will use recognized CAN/ULC-S561 active or passive forms of communication as referenced in the Fire Code and Building Code.  The use of recognized forms of communication equips a monitoring company with the ability to monitor the communication status of your alarm system in a variety of ways, giving them the flexibility to a satisfy a number of communication disruption scenarios that may exist at your facility.

Active Alarm Monitoring

Active alarm monitoring means that the communication channel between your building and a SRC is actively supervised.  This supervision is done every 180 seconds with an acknowledgement of successful communication lines between the monitoring transmitter in your building and the monitoring receiver in the SRC.  This means that if there is a communication failure between your building and the SRC, the operators will be notified about it within 180 seconds of its occurrence.  Systems that utilize active alarm monitoring are typically very stable, and have little service downtime.

Systems that utilize active monitoring include:

  • Cellular
  • IP – provided that a 24-hour battery back up is present.

Passive Alarm Monitoring

Passive alarm monitoring is simply less regular supervision of the communication channel between your building and the SRC.  In a passive monitoring scenario, the check-in is done once daily at a predetermined time.  A passive system that receives an acknowledgement and then experiences a disruption would not be identified until they miss their next scheduled check-in; for this reason, dual path monitoring is required, which allows a second form of passive communication to supervise the other.

Passive forms of monitoring can include:

  • Phone line
  • Cellular
  • IP

CAN/ULC-S561 Monitoring Standard

CAN/ULC-S561 states that when passive forms of communication are used, two non-redundant forms of communication need to be present.  In this scenario, each form of communication monitors the other; this way, if one form of communication is lost, the second notifies the SRC and confirms the activity.  For example, if a phone line is interrupted and cellular communication is used as a second method, the cellular line would transmit a signal to the SRC advising them that the phone line is not working.  Any signals that are sent by the alarm panel during this time would still be transmitted through the cellular line.

In the event of a complete communication failure, the CAN/ULC-S561 standard requires that a ULC-Listed SRC has five minutes to notify the customer that their building is in communication failure.  If the communication failure persists, the customer’s facility will be placed on “manual watch”, which means that if an alarm is triggered, someone at the building must call 9-1-1.

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For 20 years, Bulldog Fire and Security has been an industry leader in fire alarm and security services, having designed, installed, and serviced a variety of systems across Southwestern, Ontario.

If you’re interested in learning more about fire alarm monitoring, call us at 1 866 670 1590, email info@bulldogsecurity.ca, or fill out the contact form below.

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