A communication module for the MXL/V Fire Alarm System, the NET-4 is a plug-in type module used to provide communication between the Fire Safety MXL and other MXL Remote Modules. It is designed to plug into an edge connector type slot on the PSR-1 Network Supply. The NET-4 provides NFPA Style 4 type communication. This communication is RS-485 operating at 19.2K Baud and is fully digital. The NET-4 also provides a port for connection of a PC. This port can be used for system diagnostics. No special programming is required for the NET-4 Module.