Each TL333 is powered by the required model SS12P 12VDC plug-in power supply and connects to the 2-wire QwikBUS™ 'bus' wiring by means of positive screw terminal connectors. There is a 9-pin 'Din' type RS232 (serial) connector which connects to the serial port of a PC which is running AlphaEntry™ software (v3.0 or later), or to the PC's USB connector by means of a model CA-USBSER or CA-USBSERV or CA-USBSERV8 serial to USB adapter cable assembly.