vhfBridge User Manual

Functional elements

Body elements

1. Screws securing the body lid. Unscrew with bundled hexagon key (Ø 4 mm).
2. Cavity for a 12V backup battery.
   

   Battery not included with vhfBridge set.

3. QR code and ID (serial number) of the device.
4. Perforated part of the body. It is necessary for tamper triggering in case of dismounting attempts.
5. Perforated part of the body for the output of wires of connected detectors and devices.

The presence of the casing depends on the vhfBridge package. Devices come in two configurations: with and without a casing.

vhfBridge board elements

1. Terminals for connecting a 12 V backup battery.
2. Power supply input 110–240 V.
3. Tamper button. Signals if vhfBridge body lid is removed.
4. Power button.
5. LED indicator.
6. QR code and ID (serial number) of the device.
7. Terminals for connecting a third-party VHF transmitter.

vhfBridge terminals

• BATT — input for 12 V DC backup power connection
• OUT — power output for the 12 V DC VHF transmitter (maximum output current 2 A)
• OUT 1…8 — vhfBridge outputs for connecting a third-party VHF transmitter

LED indication

vhfBridge LED indicator may light up white, red, or green, depending on the status of the device.

Please note that the LED indicator is not visible when the body lid is closed. The LED indicator is used at the stage of connecting and configuring the vhfBridge. In the future, the state of the device can be monitored in the Ajax app.

LED indication of output status

Operating principle

vhfBridge is designed to connect third-party VHF transmitters to create an additional channel for transmitting events to the CMS.

The communication channel with the CMS created using vhfBridge can be used as the only or as a backup channel for communicating with the CMS (more reliable option). This means that the hub can simultaneously transmit all events and alarms to the monitoring station of the security company not only through SIA, Contact ID, and other proprietary protocols but also using vhfBridge.

The transponder receives information about alarms and events from the hub via the Jeweller radio channel. vhfBridge then transmits it to a third-party VHF transmitter over the wires. The VHF transmitter, in turn, transmits all events and alarms to the CMS via a radio channel.

Events can be transmitted to the CMS via the internet and vhfBridge in parallel. Transmission via the internet works as the main channel because of greater reliability and informativity. The transmitted events may contain the zone number of the triggered detector, group number, user number, and other data.

vhfBridge works as a backup communication channel and duplicates all events transmitted via the internet. The delivery speed of events and alarms in both cases does not exceed 1 second.

An example of the algorithm of actions in case of an alarm from a MotionProtect motion detector:

1. MotionProtect has detected an alarm.
2. MotionProtect transmits the alarm to the hub via the Jeweller radio protocol.
3. The hub receives the MotionProtect alarm and transmits it to vhfBridge via the Jeweller radio protocol.
4. vhfBridge receives the alarm from the hub and transmits it to the third-party VHF transmitter over a wired connection.
5. The VHF transmitter receives the alarm and transmits it to the radio receiver on the CMS side via the radio channel.
6. The radio receiver receives the alarm and transmits it to the CMS software.
7. The CMS receives and processes the alarm.

Output types

vhfBridge has 8 potential outputs for connection to a VHF radio transmitter. There are two types of outputs:

1. High potential output (positive trip).
2. Low potential output (negative trip).

The positive trip (high-potential output) does not supply voltage in the normal state. As soon as an alarm or event occurs, the output supplies a voltage of 12–14 V DC. The negative trip (low-potential output) works the other way around. In the normal state, the voltage is maintained at 12–14 V DC, and when an alarm or event occurs, the voltage drops to 0 V.

The vhfBridge output type and alarm pulse duration are configurable in Ajax apps.

VHF transmitter power supply

vhfBridge can supply a third-party VHF transmitter with 12 V power (maximum output current 2 A).

If the VHF transmitter has a current consumption of more than 2 A, it can be powered by the vhfBridge battery. In this case, disable battery charge tracking in the vhfBridge settings so that the system users do not receive notifications about the vhfBridge battery charging too long.

vhfBridge event transmission to the monitoring station

Ajax security system can also connect to the CMS and transmit alarms to the monitoring station in Sur-Gard (ContactID), SIA DC-09, and other proprietary protocol formats. See a complete list of supported protocols here.

The vhfBridge loop (zone) number can be found in the device states:

1. Sign in to the Ajax app.
2. Go to the Devices menu.
3. Select vhfBridge. The loop (zone) number is displayed at the very bottom of the page.

The vhfBridge loop (zone) number is also available in the Groups menu (Ajax app → Devices → Hub → Settings → Groups). To learn the loop (zone) number, select the group in which the transponder or the required connected device is located. The Device number corresponds to the loop (zone) number.

Adding to the system

vhfBridge is incompatible with Hub, ocBridge Plus, uartBridge, and third-party security central units.

Before adding a device

1. Install the Ajax PRO app. Create an account. Add a hub to the app and create at least one virtual room.
   

   You can add vhfBridge only in the PRO Ajax app.

2. Check that the hub is on and has access to the internet (via Ethernet cable, Wi-Fi, and/or mobile network). You can do this in the Ajax app or by checking the hub logo on the faceplate. The logo should light up white or green if the hub is connected to the network.
3. Ensure that the hub is disarmed and does not start updates by checking its status in the Ajax app.

Only users or PRO with administrator rights can connect vhfBridge to the hub.

In order to connect vhfBridge

1. Open the Ajax app. If your account has access to multiple hubs, select the one to which you want to add vhfBridge.
2. Go to the Devices tab and click Add device.
3. Name the transponder, scan or enter the QR code manually (located on the device body and packaging), and select a room and a group (if the group mode is activated).
4. Click Add; the countdown will begin.
5. Switch on vhfBridge by holding the power button for 3 seconds. Keep in mind that the hub connection request is only transmitted when the integration module is switching on.

For the detection and pairing to occur, the transponder should be located within the coverage area of the hub’s wireless network (at the same guarded object).

If the connection has failed, disconnect vhfBridge for 5 seconds and try again. If the transponder has already been assigned to another hub, turn off vhfBridge and then follow the standard addition procedure.

The connected transponder will appear in the list of hub devices in the app. Updating device statuses depends on Jeweller settings. The default status update period in the app is 36 seconds.

Faults counter

When a vhfBridge malfunction is detected (e.g., no external power), the Ajax app will display a red icon with a number in the upper left corner of the device icon. The number indicates the number of faults.

All faults can be seen in the transponder states. Fields with faults will be highlighted in red.

Icons

Icons display some vhfBridge states. You can view them in the Ajax app, in the Devices tab.

Icon	Meaning
	Jeweller Signal Strength. Displays the signal strength between the hub and vhfBridge. The recommended value is 2-3 bars.
	The charge level of the battery connected to vhfBridge.
	Displays when vhfBridge is operating via a ReX radio signal range extender.
	vhfBridge is temporarily disabled. Learn more
	vhfBridge tamper triggering events are temporarily disabled. Learn more

States

States can be found in the Ajax app:

1. Go to the Devices tab.
2. Select vhfBridge from the list.

vhfBridge settings

Settings can be changed in the Ajax app:

1. Go to the Devices tab.
2. Select vhfBridge from the list.
3. Go to Settings by clicking on the icon in the upper right corner.
4. Set the required parameters.
5. Click Back to save the new settings.

Note that after editing the settings, you should click the Back button to save them.

Configuring vhfBridge outputs

By default, vhfBridge outputs are configured as follows:

• 1st output — intrusion
• 2nd output — panic button
• 3rd output — malfunction
• 4th output — tamper
• 5th output — loss of vhfBridge power supply
• 6th output — power loss of the hub
• 7th output — hub battery discharged
• 8th output — loss of communication between the hub and vhfBridge

The settings of outputs can be changed in the Ajax app:

1. Go to the Devices tab.
2. Find vhfBridge in the list of devices.
3. Go to the Outputs menu.
4. Find the output in the list and go to its Settings by clicking on the gear icon .
5. Set the required parameters.
6. Click Back to save the new settings.

Event types of vhfBridge outputs

Event type	Description	Icon
Not assigned	Output disabled
Intrusion alarm	The alarm of opening, movement, and breaking of detectors
Fire	Fire alarm
Medical alarm	Medical alarm Button
Panic button	Panic button clicking in Ajax apps Clicking DoubleButton Clicking ​Button in panic button mode Clicking a panic button connected to Transmitter or MultiTransmitter
Any alarm	Alarm of any connected detector
Malfunction	Any malfunction of the connected detectors
Power loss of the transponder	Loss of main power of vhfBridge
Transponder battery discharged	vhfBridge battery discharged
Power loss of the hub	Loss of hub main power
Hub battery discharged	The hub battery is discharged
Lid	Tamper triggering of any device
Change of security modes	Changing the security mode of an object or a group (bistable output)
Confirmed intrusion alarm	Confirmed alarm (according to PD 6662: 2017) Learn more
Confirmed hold-up device alarm	Confirmed hold-up device alarm (according to PD 6662:2017) Learn more
Lost connection with vhfBridge	Loss of vhfBridge connection with the hub via Jeweller channel

The following vhfBridge outputs work in the bistable mode:

• Arming status
• Hub power
• vhfBridge power
• Hub battery status
• vhfBridge battery status

All other outputs work in the pulse mode.

Connecting VHF transmitter to vhfBridge

List of recommended VHF transmitters

• Hawk VHF Alarm Transmitter from FSK Electronics
• TX750C from RDC
• TR-41 from Puper

vhfBridge can be connected to any VHF transmitter with relay inputs. Connection via UART, RS-485, and other interfaces is not supported.

How to connect a VHF transmitter to vhfBridge

When connecting the VHF transmitter, do not twist the wires together, but solder them. The ends of the VHF transmitter wires, which will be inserted into the vhfBridge terminals should be tinned or crimped with a special sleeve.

1. Turn off the vhfBridge power (if power was connected).
2. Turn off vhfBridge.
3. Select vhfBridge outputs to which you want to connect the VHF transmitter.
4. Pull the VHF transmitter wires into the vhfBridge body through the holes.
   

   There are perforated sections on the body that can be broken off and the cable can be pulled through them.

5. Connect the VHF transmitter to the control outputs of vhfBridge according to the wiring diagram in the User Guide supplied by the VHF radio transmitter manufacturer.
6. Fasten the cable securely to the vhfBridge terminals using a straight screwdriver (slot PL 3.0).
7. Connect the power to the third-party VHF transmitter.
   

   If a VHF transmitter requires 12 V power to operate, it can be connected to the power terminals of the corresponding vhfBridge zone. Do not connect the external power supply to the transmitter power terminals, as this may damage the device.

8. Connect power to vhfBridge.
9. Turn on vhfBridge.

vhfBridge functionality testing

Integration module functionality tests do not begin immediately, but not later than over a single ping period of the hub — detector (36 seconds with the standard settings of the hub). You can change the ping period of devices in the Jeweller menu of the hub settings.

Tests are available in the device settings menu:

1. Sign in to the Ajax app.
2. Go to the Devices menu.
3. Select vhfBridge.
4. Go to Settings .

Available tests:

• Jeweller Signal Strength Test

Selecting vhfBridge placement

The placement of vhfBridge determines its distance from the hub and the presence of obstacles between them that impede the passage of the radio signal: walls, inter-floor constructions, or large-sized objects located in the room.

Be sure to check the signal strength at the installation site. If the signal strength is low (a single bar), we cannot guarantee a stable operation of the security system. At the very least, relocate the device as repositioning even by 20 cm can significantly improve the signal reception.

If poor or unstable signal strength is still reported after the relocation of the device, use the ReX radio signal range extender of the security system.

When choosing the installation location, consider the distance between vhfBridge and the VHF transmitter — the cable length should be sufficient for connection.

The minimum distance between vhfBridge and the radio transmitter is 2 meters and the maximum distance is 7 meters. The minimum distance is required to avoid signal overlapping. The maximum distance allowed will help avoid signal attenuation in the cable.

The material and cross-section of the cable for connecting the VHF transmitter are determined by the requirements of the manufacturer of the VHF transmitter and the maximum current value. All requirements can be found in the manual or from the customer service of the VHF transmitter manufacturer.

vhfBridge installation

Prior to mounting vhfBridge, ensure that you have selected the optimal place to install the device corresponding to these instructions.

The transponder body should be mounted on a vertical surface. If installed on a horizontal surface, the tamper will not work when attempting to dismantle the transponder.

To install a transponder:

1. Secure the body to the surface with bundled screws using at least two fixing points. In order for the integration module tamper to respond to a dismantling attempt, be sure to fix the body at the point with the perforated section.
2. Install the vhfBridge card into the body on the racks. If available, connect a backup battery. Note that a power supply should not be connected to the terminals.
   

   We recommend using a 12 V battery with a capacity of 4 or 7 Ah. For such batteries, special racks in the body are designed. You can also use similar batteries of a different capacity, of matching size, with the maximum full charge time of no more than 30 hours. The maximum battery size for installation in the body is 150 × 64 × 94 mm.

3. Connect the VHF transmitter to vhfBridge.
4. Turn on vhfBridge.
5. Install the lid on the body and fix it with the bundled screws.

After installation, be sure to check the vhfBridge tamper status in the Ajax app.

Do not install vhfBridge:

• Outdoors. Doing so may cause the device to malfunction or not work properly.
• Near metal objects or mirrors (for example, in a metal cabinet) They can shield and attenuate the radio signal.
• Inside premises with temperature and humidity outside the permissible limits. Doing so may cause the device to malfunction or not work properly
• At a distance less than 1 meter from the hub or a range extender. This could result in the loss of connection with the hub.
• At a distance less than 2 meters from the VHF transmitter or a range extender. The minimum distance is required to avoid signal overlapping.
• At a distance more than 7 meters from the VHF transmitter. The maximum distance allowed will help avoid signal attenuation in the cable.

Maintenance

Check the functionality of vhfBridge regularly. The optimal frequency of checks is once every three months. Clean the body from dust, cobwebs, and other contaminants as they emerge. Use a soft, dry cloth that is suitable for equipment care.

Do not use any substances containing alcohol, acetone, petrol, and other active solvents to clean the device.

Technical Specifications

Complete set

1. vhfBridge.
2. Power cable.
3. 12 V battery connection cable.
4. Installation kit.
5. Body (depends on the configuration).
6. Quick Start Guide.

Warranty

Warranty for the AJAX SYSTEMS MANUFACTURING Limited Liability Company products is valid for 2 years after the purchase.

If the device does not work correctly, you should first contact the support service. In half of the cases, technical issues can be solved remotely.

Contact Technical Support:

• e-mail
• Telegram