PTI's RS-232 Serial Interface Adapter (SIA) is a 9 pin RS485 to RS232 adapter designed for PTI’s SiteMaster Graphics. This simple plug and play device uses the positve, negative, and common data wires from the Falcon Security System to communicate to the SiteMaster program. This SIA uses any free and working COM port on the computer and is enhanced with lightning and surge protection circuitry.