Nord GSM: Siren

The article is relevant for the control panels "Nord GSM" hardware version 5.x

«Siren» output

The output is designed to connect the sound alarms (sirens) that meet the following requirements:

  • the siren should have a built-in audio frequency generator;
  • the siren should be designed for 12V supply voltage;
  • the current consumed by the siren should not exceed 150 mA.

If in the settings of the device it is indicated that the siren is connected, then the line of communication with the siren is monitored, which allows to detect the break and the short circuit of the line, both when the siren is off and on. If any of these faults is detected, a generalized signal “Siren faulty” is generated, which is transmitted to the security console (event code E321).

For panels «Nord GSM Mini» and «Nord GSM Air» the alarm configuration algorythm is described in a separate article.

Siren activation

The activation (switching on) of the siren is performed only if the device settings indicate that the siren is connected.
The siren is activated only in case of alarm in the loops described as “Security”, “Fire” and “24-hour”.

Siren actuation interval

If the siren is turned on with an alarm in the loop, described as “Security”, then the siren will turn off either at the expiration of the interval set by the “Siren sound interval” parameter, or when the partition in which the alarm loop enters.

If the siren is turned on when there is analarm in the loop, described as "Fireman" or "24-hour", then the siren will be turned off either after the interval set by the "Siren sounding interval" parameter or when typing on the keyboard the code to desactivate it (5422).

Repeated activation of siren

For loops configured as “Security”:

  • if the siren was turned off because the loop was disarmed, then the siren will not be turned on again for this loop until the loop is armed;
  • if the siren has been turned off because the siren’s sound interval has expired, then the siren will be turnedon again for this loop only as a result of repeated alarm on the loop.

For the loops described as "Fire" or "24-hour":

  • if the siren has been turned off because the siren has elapsed, then the siren will only be turned on after the siren has re-started (5 minutes);
  • if the siren was turned off because the user dialed the code for turning off the siren on the keyboard, the siren will be turned on again after the siren re-activates (5 minutes).

Frequently asked questions

Why does a voltmeter show 12 Vall the time at terminals?

If you are trying to check the algorithm of the device with a siren, connecting a voltmeter to the terminals, then you will constantly see +12 V on the voltmeter. The device always keeps a 12 V siren at the output to monitor the performance of the circuit.

Why does a siren work in a half tone when there is no alarm?

If a siren has a large internal resistance,then it can “buzz” without alarm. To rectify this, it is recommended to connecta 1 kOhm resistor in parallel with the siren. At the same time, in order not to lose control of the communication line with the siren, the resistor should be connected not to the terminals of the device, but in the immediate vicinity of the siren.

How many wired sirens can be connected to the device?

The quantity is determined by the current consumption of the siren itself, which you want to connect, with a nominal voltage of 12 V.


  • Siren СВИРЕЛЬ-2 cannot be used, since the current of consumption of 300mA indicated on it exceeds the capabilities of Nord GSM.
  • АС-10 Siren (ООПЗ-12) With a current consumption of 90 mA, it is desirable to use a single copy, although at normal (room) temperatures it is possible to connect two.
  • Siren ОПЗ СТАНДАРТ with a current consumption of 50 mA, three pieces can be connected, and sirens ИВОЛГА (ПКИ-1) much more because it is the most economical (30 mA).

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