Ajax Wireless StreetSiren Black Front SD421B
Ajax Wireless StreetSiren Black Front SD421B
Ajax Wireless StreetSiren Black Left Side SD421B
Ajax Wireless StreetSiren Black Right Side SD421B
Ajax Wireless StreetSiren Black Back SD421B

Ajax Wireless StreetSiren Black

R 2,335.00 Incl. VAT
R 2,459.00 Incl. VAT

Available to order online or collect at 6 Cosmic Street Linbro Park, Sandton, 2090 (Map)


 Product Code: 7661.07.BL1

The Ajax StreetSiren is a wireless outdoor siren that notifies you of danger using sound and light. The device is installed outside the room to raise an alarm for everyone to hear.

  • Authentication to prevent forgery
  • Jamming detection and communication channels encryption
  • Tampering alarm

Resistant to dust, hail and rain drops. Operates at a temperature of −25°С

Indicates armed/disarmed mode with a built-in LED

Operates up to 5 years without battery replacement or from 12 V DC power supply

Principle of operation

The device notifies of detector activation with an audible alarm and LED. Sound level and alarm length are set in the mobile application.



The device has IP54 dust and moisture protection. 12 V DC external power supply can be connected, if necessary. The built-in accelerometer will raise the alarm if an attempt is made to remove the siren.


Installation and set up

Ready to operate straight out the box: the battery is already installed, therefore there is no need to disassemble the siren. With one click, it can be connected to the hub in the mobile application. It can be mounted on the SmartBracket in just a few minutes.


Tech specs


Light and sound radio channel security sounder

Type of detector


Installation method



Operates only with Ajax Hub, Ajax Hub Plus and Ajax ReX

Type of notification


Sound volume level

Adjustable, 81−113 dB at a distance of 1 m

Alarm length

Adjustable, 3−180 s

Indication of armed/disarmed status


Alarm signal delivery time

0.15 s

Power supply

Battery: Four CR123A batteries

Power supply voltage: 3 V

Battery life — up to 5 years

Mains supply: DC 12 V±20%

Jeweller radio technology

Communication range with central unit — up to 1,500 m in an open space

Two-way communication between devices

Operating frequencies — 868.0-868.6 MHz

Self-adjusting RF output power — up to 25 mW

Block encryption based on AES algorithm

Device polling period — 12−300 s

Temperature sensor


Operating temperature range

-25°С to +50°С

Permissible humidity

Up to 95%

Protection class of body



Protection against fraud

Jamming detection


Remote setting and testing



200х200х51 mm


528 g


Grade 2, CE


Replacement and repair within 24 months of the date of sale. Batteries are not covered under warranty.

Complete set

StreetSiren siren

SmartBracket mounting panel

4 batteries CR123A (pre-installed)

Installation set

User’s guide