The ELK-M1XSP Lighting/Thermostat Interface, Serial Port Expander is a "3 in 1" product. As a lighting interface, it adapts the M1 Gold or M1EZ8 Control to many brands of Lighting control products which use “serial" communications. i.e.,OnQ-ALC, PCS-UPB, EDT, CENTRALITE, VANTAGE, etc. As a thermostat interface, it adapts the M1 Gold or M1EZ8 control to HVAC Communicating Thermostats from companies such as:RCS, APRILAIRE, and HAI. As a serial port expander, it expands the RS-232 communication ports of the M1Gold or M1EZ8 for multiple connections to most any type of equipment that communicates using serial ASCII commands. i.e., Personal Computers and high end whole house subsystems such as: CRESTRON, AMX, etc. Jumpers on the M1XSP select the appropriate application, connection, and protocol. Best of all, the M1XSP operates from the 4-wire (RS-485) M1 Keypad data bus, allowing RS-232 ports to be located long distances from the control. The M1 Gold and M1EZ8 support up to 7 M1XSPs. The communications baud rate is adjustable from 300 to 38,400 baud. The unit comes complete with cable and a black surface mountable housing.