SerialGear&reg; Single Port USB to RS-232 Selectable RS-422 or RS-485 Industrial Adapter Adds a high speed RS-232/422/485 serial port via USB connection Serial Connector: one DB-9 male connector, and one 6-pin Terminal Block Supports RS-232, RS-422 Full Duplex, RS-485 Half Duplex and RS-485 Full Duplex modes. LEDs which show transmitting and receiving of data. Self-powered (from USB), does not require external power.