CTM
The CTM City Tie Module is an interface between the control panel notification appliance circuit and a master box. It provides off-premises signal transmission for systems that must comply with NFPA requirements for Auxiliary Protective Systems. The CTM activates a local energy fire alarm box, which provides a 24V DC alarm signal (current limited at 200 mA).
RPM
The Edwards RPM Reverse Polarity Module is an interface between FireShield and a reverse polarity receiver. It provides off-premises signal transmission for systems that must comply with NFPA requirements. When used as a reverse polarity remote station or central station transmitter, it can be connected to either a single circuit (alarm, or alarm and trouble) or to up to three circuits (alarm, supervisory, and trouble).

The RPM must be mounted in an MFC-A enclosure immediately adjacent to the panel and in conduit.