Reference:
TC809EA1035
The TC809EA1035 monitor module can be installed in a single gang junction box directly behind the monitored unit. Its small size and light weight allow it to be installed without rigid mounting (see Figure 1). The TC809EA1035 is intended for use in intelligent, two-wire systems where the individual address of each module is selected using rotary decade switches. It provides a two-wire initiating circuit for normally open contact fire alarm and security devices.