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ANPR Whitelist with IP Relay

Automate on-site responses by whitelisting licence plates to trigger IP relays for gate opening and device control.

Step 1: Add Plates to Whitelist

1. Go to Admin → Cameras → select your ANPR camera → ANPR Plates tab

2. Fill in the Add New ANPR Plate form:

   • Plate Number: Enter the licence plate without spaces (e.g., 181KE2568 not 181K E256 8)
   • List Type: Select Whitelist or Blacklist
   • Expiry Date: Optional - plate deactivates automatically after this date

1. Click Create to add the plate

Whitelist vs Blacklist:

• Whitelisted plates trigger relay automation (e.g., open gate)
• Blacklisted plates send notifications to users but do not trigger relays

Step 2: Add a Relay Device

1. Go to Admin → Cameras → select your ANPR camera → Relay Devices tab

2. Fill in the Add New Relay Device form:

   • Device: Select the IP relay device from your Devices list
   • Username/Password: Credentials to access the relay device
   • On Path: HTTP path to activate relay (see path format below)
   • Off Path: HTTP path to deactivate relay (see path format below)
   • Status Path: HTTP path to check relay status
   • Outputs Number: Number of relay channels available on the device

3. Click Create to add the relay device

Understanding Relay Path Format

There is no universal standard for IP relay control - each manufacturer uses their own HTTP protocol. The defaults use the Robot Electronics protocol (ETH002, ETH008, ETH484 series):

• On Path: /io.cgi?DOA%1$s=%2$s - DOA = Digital Output Active
• Off Path: /io.cgi?DOI%1$s=%2$s - DOI = Digital Output Inactive
• Status Path: /status.xml

The %1$s and %2$s are placeholders that TetherX replaces automatically:

• %1$s = Output channel number (1, 2, 3, etc.)
• %2$s = Duration in 100ms increments (10 = 1 second, 30 = 3 seconds, 0 = permanent)

Testing Your Relay Device

Before configuring automation, test your relay directly by entering these URLs in your browser (replace 192.168.1.100 with your relay's IP):

Step 3: Link Camera to Relay Device

After creating a relay device, configure your camera to use it:

1. In the same Relay Devices tab, scroll to Camera Relay Configuration

2. Configure the following settings:

   • Relay Device: Select which relay device this camera should control
   • Output Number: Which relay output channel to use (1-based)
   • Duration: How long to activate the relay in seconds (e.g., 3 seconds for a gate)

3. Settings save automatically when you make changes

How Automation Works

When a whitelisted plate is detected:

1. Camera detects licence plate and sends it to your TetherBox
2. TetherBox matches plate against the camera's whitelist
3. If matched, TetherBox sends ON command to configured relay device
4. Relay activates (e.g., gate opens)
5. After the configured duration, TetherBox sends OFF command
6. Relay deactivates (e.g., gate closes)

Troubleshooting

Barrier Not Opening for Whitelisted Plates

If the relay doesn't trigger when a whitelisted plate is detected, check the following:

1. Verify Camera Relay Configuration (most common issue)

Go to Admin → Cameras → select your camera → Relay Devices tab → scroll to Camera Relay Configuration and confirm:

• A Relay Device is selected (not "None")
• Output Number matches your relay channel
• Duration is set (e.g., 3 seconds)

2. Check the "Last Seen" Column

In the ANPR Plates tab, the Last Seen column shows when each plate was last matched:

• Never updated = Plates are being detected but not matched to whitelist entries
• Updates but relay doesn't trigger = Whitelist matching works, but relay configuration is wrong

3. Plate Format Must Match Exactly

The plate number in your whitelist must match exactly how the camera stores it:

• Plates are stored without spaces (e.g., 181KE2568)
• The display adds spaces for readability (e.g., 181K E256 8) but this is cosmetic only
• Export your ANPR data to CSV to see the actual stored format
• Enter plates without spaces to ensure matching works

4. Check TetherBox Connectivity

Go to TetherBoxes and verify your TetherBox is online. If offline, the whitelist data cannot sync and relay commands cannot be sent.

5. Resync Plates to TetherBox

If plates appear correct in TetherX but the TetherBox isn't recognising them, use the Resync Plates button:

1. Go to Admin → Cameras → select your ANPR camera → ANPR Plates tab
2. Click the Resync Plates button in the top-right corner of the ANPR Plates card
3. This deletes all plates stored on the TetherBox and re-sends them from the database

Use this when:

• Plates were added while the TetherBox was offline
• The TetherBox was replaced or rebuilt
• Whitelist matching isn't working despite correct configuration

6. Test the Relay Manually

In the Relay Devices tab, each relay device has test buttons in the table:

• ON - Activates the relay
• OFF - Deactivates the relay
• Pulse - Activates for 2 seconds then deactivates

If manual testing fails:

• Check relay device credentials (username/password)
• Verify the relay is on the same network as the TetherBox
• Test the relay URL directly in a browser (see path examples above)

7. Check Expiry Dates

Plates with past expiry dates are automatically ignored. Remove the expiry date or set a future date.

Related Articles

• Setting Up ANPR Cameras - Configure ANPR on your cameras
• How to Enable ONVIF - Enable ONVIF protocol for camera discovery