A duress button is an example of a "Dry Contact" device. Dry contact is a synonym for 'no voltage'. Since to detect that the push button is closing, we aren't needing to provide any power. We are just detecting when there is a closed circuit, and when there is an open circuit.
We set up with a Normally Open push button switch, one side connected to one of the 3 Digital Inputs and the other to ground.
To use either Digital Input 1, 2 or 3, you will need to use the corresponding wires.
- Digital Input 1 = PINK
- Digital Input 2 = BLUE
- Digital Input 3* = GREEN
*Digital Input 3 is shared with one of the Driver ID lines, so DI3 cannot be used at the same time as a DM RFID reader, or Wiegand Reader.
In this configuration, when the button is OFF (switch open) it is
- Not pressed
- an open circuit,
- and there is no complete path from the input to ground.
When the button is ON (switch closed) it
- Is pressed
- closes the loop.
- Connects the input to a low signal (GND)
The configuration would be:
- Bias resistor set to 'pull up'
- When the button is not pressed (OFF) and nothing is connected to the input, the input is held high (so we consider this level 'off' (active level = low)
- The Active Level is set to low
- When the button is pressed (ON) the input is pulled to ground.
- The digital input is considered on when the button is pushed.
- We want immediate notification of duress button pushes, so we set Log on Active and Upload on Active to Yes.
If you have a No Comms Zone configured when setting up Geofence Downloads to Device, the Emergency Uploads parameter can be set to Yes. This means that the device will be able to do emergency uploads, like when panic button is pressed, even when it is in a no communications zone.
Alerts in Third-Party Platforms
When the state of a digital input changes a record will be sent with Log Reason 9 - Digital Input Changed.
Then to determine which input has changed, Field ID = 2: Digital Data contains the state of all digital inputs.
Alerts in Telematics Guru
See the guide here - Panic/Duress Alert on Telematics Guru