The Standard Series 65 Relay Base, 45681-245, provides one set of volt-free, changeover (form C) contacts that change state when the detector signals an alarm.

Series 65 Relay Bases are primarily intended for use with control units using 4-wire detector supply and alarm initiating circuits. Where local codes allow, they may also be used in 2 and 4-wire circuits to provide volt-free control signals to an auxiliary system such as an automatic door closer. 

They are not suitable for use in systems where it is specified or required that operation of the auxiliary system shall be fail-safe and must not be used with any other type of detector.