This is a USB to RS-232 interface adapter cable. No external power supply needed. Compatible with USB and RS-232 standards, this is capable to perform the conversion from single-ended USB signal into UART signal of RS-232. DB9 male connectors are used for connection from RS-232 interface. The unique I/O circuit of the internal zero delay auto transceiver contained in the converter controls the data stream direction automatically. The converter is plug-and-play. Power indicator light and data traffic indicator light are also available with the converter for malfunction indication. Features include... 60" Industrial Grade Cable Conforming to USB Ver1.0, 1.1 and 2.0 and EIA RS-232. USB signals: VCC, DATA+, DATA-, GND and FG.. RS-232 signals: DCD RXD TXD DTR GND DSR RTS CTS RI Working mode: asynchronous point-to-point. Direction control: adoption of automatic data stream control for automatic recognition and control of data transmission direction. Baud rate: 300 to 921.6Kbps, automatic detection of the transmission rate of the serial interface signal. Interface protection: +-15KV electrostatic protection. Interface : USB female connector and DB9 male connector. Transmission media: twisted-pair cable or shielded cable.