The ADP3133T is an interface converter that allows users to link RS232 and RS422 equipment. The ADP3133T comes equipped with a DTE/DCE switch. When set to DCE, the ADP3133T can plug straight into a PC DB09 serial port. The RS422 jack can take either a RJ11 or RJ45 plug. Center two wires (3&4) are Transmit data while the next pair of wires (2&5) are Receive data.