# Multi-use Catalyst Relay Driver

When there is at least one destination configured as PA the Catalyst relay driver output operates very much like a “press-to-talk” type switch. This switch is activated only for the short duration of PBX/Local Paging System alarm annunciations. The relay driver output is intended to source current for a 5 VDC reed relay and should only be used for that purpose.

Caution: Uses of the relay driver output that draw more than 20 milliamps will compromise the Catalyst system operation.

Connection of the reed relay is made on the Catalyst I/O board (mainboard) at the header pins, P4 (see diagram CIG Rev D). P4 – Pin 1 is the output of a PNP transistor and P4 – Pin 2 is ground. There is a diode between the P4 pins to short out the inductive kick of a relay coil.