6
When the input signal is idle or grounded, the device can collect the different statuses of the
alarm input port. When the input signal is connected to 3.3V or it is idle, the device collects the
logic “1”. When the input signal is grounded, the device collects the logic “0”.
Figure 2-3
Step 2
Connect alarm output device to the alarm output of I/O cable, alarm output is collector open
circuit output which connects pull-up10K resistor to 3.3V externally.
Mode A:
Level application. Alarm output high and low level, alarm output is OC; it needs to
increase pull-up resistance externally to work normally. Max external pull-up level is 5V, max
port current is 5mA (peak). After external pull-up resistance is increased, the default output
signal is high level (external pull-up voltage), and it switches to low level when there is alarm
output. (Output voltage is less than 0.8V when working current is 5mA)
Mode B:
Switch application. Alarm output is used to drive external circuit, max voltage is 5V
and max current is 30mA (peak), it is recommended to add an external relay when it is
beyond the value.
Figure 2-4
IR Bullet Network Camera Quick Start Guide
