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 = BLUE
- Digital Input 2 = ORANGE
- Digital Input 3* = PURPLE
*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.
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