Issue Summary

The Alarm Output connection on modern network cameras is not a contact closure but a voltage level change. This pertains to all network cameras with an Alarm Out port.

Resolution

The following diagram shows the circuit needed to create a relay operated closure.

An easier solution is to utilize a ready-made relay module available in many different versions similar to the ones pictured in the following images.

NOTE: Besides the relay module, a DC power-supply may be needed.