The ANN-I/O is an LED driver module that can be used in a wide variety of applications including as an interface with the Fire Alarm Control Panel (FACP) to drive most customized graphic annunciators. It comes in a plastic enclosure that may be mounted inside a custom annunciator or accessory cabinet and can drive up to 40 LEDs.

The ANN-I/O and the FACP communicate over a two-wire serial interface employing the ANN-Bus communication format. An additional two wires are used for 24-volt DC power. A single four-conductor unshielded cable may be used for both power and data communications.

Up to eight ANN-Bus devices may be connected to the ANN-Bus of each FACP.