Ajax VHF Bridge Black Image 1
Ajax VHF Bridge Black Image 1
Ajax VHF Bridge Black Image 2
Ajax VHF Bridge Black Image 3
Ajax VHF Bridge Black Image 4
Ajax VHF Bridge Black Image 5
Ajax VHF Bridge Black Image 6
Ajax VHF Bridge Black Image 7

Ajax VHF Bridge Black

R 2,515.00 Incl. VAT

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



Module for connecting Ajax Security Systems to third-party VHF transmitters

Instant alarm transmission without Internet


vhfBridge is a transponder that provides a hub with an additional channel to communicate with a monitoring station. With vhfBridge you can use Ajax systems in cities where Internet connection is unstable, in nature reserves, mountain and desert areas.


 Alarms and events of the system are transmitted via VHF radio waves over tens of kilometres1.

 vhfBridge can be used as a primary or a backup communication channel.

Reliability and versatility by design


  • Place for a backup battery2 150 × 64 × 94 mm
  • Perforated areas in the casing3 for accurate cable management
  • 8 adjustable positive/negative trip outputs for sending events to a VHF transmitter
  • VHF transmitter power supply 12 V DC, 2 A
  • Casing protected from sabotage tampers detecting opening and removal from the surface3

Elaborate autonomy


You can build in a 7 Ah backup battery inside a vhfBridge casing. It will feed a VHF transmitter with up to 2A current consumption. Therefore, the transmitter doesn't need to have a separate battery, which makes maintenance less frequent. In case of a power outage at a facility, the transponder and the transmitter operate on a backup battery for up to 75 hours4 while still transmitting events to a central monitoring station.


  • Up to 75 hours4 of autonomous operation
  • Place for a 7 Ah backup battery

Adjustable signalling


Get only events you need. You can configure each vhfBridge output in the Ajax app: set an event or disable it.

Uncompromised security of communication


vhfBridge communicates with a hub via an encrypted Jeweller radio protocol. It guarantees continuous interaction of all security system devices. The radio protocol uses frames to synchronize device communication sessions, authentication to prevent forgery, and encryption to protect against data theft.


  • Connection with a hub at a distance of up to 1,800 meters
  • Alarm transmission within 0.15 seconds
  • Hub ping interval from 12 seconds

Hassle-free installation


Similar to other Ajax devices, vhfBridge connects to a hub in the app by scanning a QR-code. The transponder casing has perforated areas for more organized wiring. Outputs are configurable with Ajax apps for smartphones and computers.

Tech specs



White and black


Transponder for communication with the monitoring station via a VHF transmitter



Number of potential outputs


Output types

Positive trip and negative trip (depends on the settings)

Transmission types

Pulse and bistable (depends on the settings)

Compatible with Ajax central units

Operates with Hub 2, Hub Plus, Hub 2 Plus

Compatible with Ajax range extenders


Compatibility with third-party VHF radio transmitters

vhfBridge connects to any VHF transmitter with relay inputs


Recommended models

Support for photo verification of alarms


Primary power supply

100–240 V, 50/60 Hz

Backup power supply

12 V DC, up to 75 hours of power for a transponder and a transmitter

Supported battery type

12 V battery with a full charge cycle of up to 30 hours.


The maximum battery size installed in the casing should be 150 × 64 × 94 mm

Recommended battery type

12 V battery with a capacity of 4 Ah or 7 Ah


Backup battery is not included in the set

VHF transmitter power

12 V DC, 2 A


Protecting against forgery

Jamming notifications

Tampers against opening and removal

Backup battery

Jeweller radio protocol

Communication range — up to 1,800 meters in a line of sight

Two-sided communication between devices

Operating frequencies: 868.0–868.6 MHz or 868.7 – 869.2 MHz (depending on the region of sale)

Auto-regulated radio signal power: ≤ 25 mW

Blocking encryption based on the AES algorithm

Detector ping interval: 12–300 seconds

Frequency hopping


Learn more about Jeweller

Maximum radio signal power

≤ 25 mW

Protection class


Operating temperature range

From −10°C to +40°C

Operating humidity

Up to 75%

Overall dimensions

196 × 238 × 100 mm (with casing)

145 × 89 × 51 mm (without casing)


840 g (with casing)

165 g (without casing)


Warranty service for 24 months from the date of sale.


Learn more

Complete set


Power cable

12 V battery connection cable

Installation kit

Casing (depends on a set)

Quick start guide


10 years


1 The distance depends on the transmitter, the terrain, and the weather. The maximum range varies in each particular case.

2 A backup battery is not included in the set

3 vhfBridge can be sold without a casing

4 When using a 7 Ah battery