Foscam FI9903P User Manual page 66

There is an IO alarm input / output lines in the FOSCAM camera tails. Enable IO alarm need this cable to
connect to the alarm device (door sensor, infrared sensor, smoke detector, etc.).
I/O Alarm has four ports:
Port 1 and port 2 indicate IO alarm input

Port 3 and port 4 indicate IO alarm output

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