FMC920: can a pulsed alarm siren signal wake the device [on DIN1] from Deep Sleep?

Telematics Question
1

Hello,

I am configuring a Teltonika FMC920 for a vehicle use case and I need clarification on Deep Sleep wake-up behavior.

My setup is:

  • ignition detection configured via DIN1,

  • a car alarm siren output is also connected to the same input through diode isolation,

  • I would like the device to wake up from Deep Sleep both on real ignition ON and on alarm trigger.

My questions are:

  1. What is the minimum stable HIGH pulse duration on DIN1 required for the FMC920 to reliably wake up from Deep Sleep when DIN1 is used as the ignition source?

  2. Will a pulsed alarm siren signal on DIN1 be detected reliably as ignition ON, or is a longer steady HIGH level required? (Siren signal, so ~500ms 0V, ~500ms 12V on loop)

  3. Is there any recommended input filtering or debounce setting for this kind of wiring?

The reason for this setup is vehicle theft protection: I want the tracker to stay in low-power mode during parking [deep sleep] , but still wake up and send an alert if the car alarm is triggered.
Yes, the alarm signal would be connected to the AIN1 too for the emergency trigger event.

Thank you!

2

Dear Team,

The FMC920 can detect a 500 ms pulse as ignition.

However, the voltage level of the pulse must be higher than 7.5 V.

Additionally, in the I/O settings, please configure the Ignition Averaging Constant to 1.

Best regards,

Naveen

3

Thank you!