vhfBridge User Manual

Updated

vhfBridge is a module for connecting Ajax security systems to third-party VHF transmitters. It provides 8 transistor outputs for connection to third-party VHF transmitters.

The device is powered from 100–240V AC mains and can be operated from a 12V— backup battery.

Not compatible with Hub, ocBridge Plus, uartBridge, and third-party security central units. Note that you can only add a device in PRO Ajax apps.

The vhfBridge operates as part of the Ajax security system by connecting via the Jeweller secure radio communication protocol to the hub. The hub communication range is up to 1800 meters without obstacles. Comes in two configurations: with and without a casing.

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 Event Note
Lights white. Connection with the hub is established, external power supply is connected.
Lights red. There is no connection with the hub, external power supply is connected. For example, the hub is turned off or vhfBridge is outside the coverage area of the hub’s wireless network.
Goes out for 0.5 seconds, then lights up green and turns off. Enabling vhfBridge.
Goes out for 0.5 seconds, then lights up green and fades out over 3 seconds. Disabling vhfBridge.
Blinks red once per second. vhfBridge is not assigned to a hub.
Lights up for a second once every 10 seconds. No external power supply is connected to vhfBridge. The colour of the indication depends on the status of connection with the hub:

  • lights up white if there is connection with the hub;
  • lights up red if there is no hub connection.
During an alarm, gradually lights up and goes out once every 10 seconds. No external power supply and discharged external battery of vhfBridge. The colour of the indication depends on the status of connection with the hub:

  • lights up white if there is connection with the hub;
  • lights up red if there is no hub connection.

LED indication of output status

LED indication Output status in case of alarm
High potential output (positive trip). Lights up green.
Low potential output (negative trip). Goes out.

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

ajax vhfbridge

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

ajax vhfbridge

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.
Parameter Meaning
Malfunction

Click to open the list of vhfBridge malfunctions.

The field is displayed only if a battery charge fault is detected.

Jeweller Signal Strength

Signal strength between the hub and vhfBridge.

The recommended value is 2-3 bars.

Connection Connection status between the hub and vhfBridge:

  • Online — the device is connected
  • Offline — no connection to the device
Battery charge

Battery charge level of the device. Displayed as a percentage.

How battery charge is displayed in Ajax apps

Also, this field can display the battery status:

  • Charging — displayed while the battery is being charged
  • Error — displayed if the battery has been charging for more than 40 hours
Lid

The status of tampers that respond to detachment or violation of the integrity of the body.

What is a tamper

External power The presence of external power supply 110–240 V:

  • Connected — external power supply is connected
  • Disconnected — external power supply is disconnected
ReX “range extender name” ReX range extender connection status:

  • Online — the device is connected
  • Offline — no connection to the device

Please note that the field is displayed if vhfBridge is operated via a ReX range extender.

Temporary Deactivation Shows the status of the device temporary deactivation function:

  • No — the device operates normally and transmits all events
  • Lid only — the hub administrator has disabled notifications about triggering on the device body
  • Entirely — the device is completely excluded from the system operation by the hub administrator. The device does not follow system commands and does not report alarms or other events
Firmware vhfBridge firmware version.
ID vhfBridge ID (serial number). Also located on the device box, its board, and the body.
Device № Number of the device loop (zone).

vhfBridge settings

ajax vhfbridge

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.

Setting Meaning
First field

vhfBridge name. It is displayed in the text of SMS and notifications in the event feed.

To change the device name, click on the pencil icon .

The name can contain up to 12 Cyrillic characters or up to 24 Latin characters.

Room

Selecting the virtual room to which vhfBridge is assigned.

The room name is displayed in the text of SMS and notifications in the event feed.

Monitoring of the battery charging duration

Set up of the battery charging duration.

When this option is enabled, the system will send a malfunction notification if the battery connected to vhfBridge has been charging more than 40 hours.

Disable monitoring if the third-party VHF radio transmitter is powered directly from the battery and not from the vhfBridge power terminals.

Pulse duration

Pulse time on an event (from 1 to 255 seconds). Set in increment of 1 second.

The default value is 5 seconds.

Jeweller Signal Strength Test

Switches vhfBridge to the Jeweller signal strength test mode.

The test allows you to check the signal strength between the hub and vhfBridge and determine the optimal installation location.

What is Jeweller Signal Strength Test

Temporary Deactivation

Allows the user to disable the device without removing it from the system.

Two options are available:

  • Deactivate entirely — the device will not execute system commands or participate in automation scenarios, and the system will ignore device alarms and other notifications
  • Deactivate lid notifications — the system will ignore only notifications about the triggering of the device tamper button

Learn more about temporary deactivation of devices

User Guide Opens vhfBridge User Guide in the Ajax app.
Unpair Device Unpairs vhfBridge, disconnects it from the hub, and deletes its settings.

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.
Setting Meaning
Event type

Selection of the event type to which vhfBridge output reacts.

A complete list of event types and their icons is available below

Connection type of the output Selection of the output type:

  • High potential output (positive trip).
  • Low potential output (negative trip).

Event types of vhfBridge outputs

Event type Description Icon
Not assigned Output disabled
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Intrusion alarm The alarm of opening, movement, and breaking of detectors
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Fire Fire alarm
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Medical alarm Medical alarm Button
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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
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Any alarm Alarm of any connected detector
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Malfunction Any malfunction of the connected detectors
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Power loss of the transponder Loss of main power of vhfBridge
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Transponder battery discharged vhfBridge battery discharged
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Power loss of the hub Loss of hub main power
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Hub battery discharged The hub battery is discharged
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Lid Tamper triggering of any device
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Change of security modes Changing the security mode of an object or a group (bistable output)
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Confirmed intrusion alarm

Confirmed alarm (according to PD 6662: 2017)

Learn more

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Confirmed hold-up device alarm

Confirmed hold-up device alarm (according to PD 6662:2017)

Learn more

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Lost connection with vhfBridge Loss of vhfBridge connection with the hub via Jeweller channel
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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:

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

General characteristics
Colour White, black
Installation Indoors
Compatible with central units Operates with Hub 2, Hub Plus, Hub 2 Plus
Compatible with range extenders +
Connections
Communication protocol Jeweller: two-sided encrypted radio protocol that transmits events and alarms
Radio signal range

Up to 1,800 meters in a line of sight

Learn more

Operating frequences 868,0−868,6 МГц
868,7–869,2 MHz
863,0–870,0 MHz
(depends on region)
Maximum radio signal power ≤ 25 mW
Third-party VHF radio transmitters integration
Number of potential outputs 8
Output types High-/low-potential outputs (set by the administrator in the app)
Transmission types Pulse and bistable (depends on the output type; the pulse duration is set in the app)
Alarms photo verification No
Recommended VHF transmitters Hawk VHF Alarm Transmitter from FSK Electronics
TX750C from RDC
TR-41 from Puper
Power supply
Main power supply 100–240V AC, 50/60 Hz
Backup power 12V DC (backup battery not included)
Supported battery type

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

The maximum battery size for installation in the body is 150 × 64 × 94 mm

Recommended battery type 12V battery with a capacity of 4 or 7 A⋅h
VHF Transmitter Power 10.5–15.5 V DC (maximum output current 2 A)
Anti-sabotage protection
Tamper +
Ping interval 12–300 sec (set by the administrator in the application)
Radio frequency hopping +
Forgery protection +
Body and configuration
Operating temperature range From -10°С to +40°С
Operating humidity Up to 75%
Dimensions 196 × 238 × 100 mm(with a casing)
145 × 89 × 51 mm (without a casing)
Weight 840 g (with a casing)
165 g (without a casing)

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:

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