Serial ports on USB allow further use of existing devices, even when the computer doesn't offer serial ports.The high speed serial port with the 128 byte transmit FIFO & 384 byte receive FIFO allow high speed communication, even in heavy loaded systems. Unique features reduce the system load. The serial port also allows unusual speed settings up to 921Kb with support to non standard Baud rates. As well the ports are protected with surge protection of 10KV. USB-4COMi-M CBL uses a small case due to the high-density DB37 kombi connector for the serial ports. Mounted even in narrow environment, it connects to serial devices via spider cable or a connection box. Supported mode are: RS-232; Standard RS-232 Mode, RS-422; 4-wire with handshaking, RS-485; 4-wire full duplex, RS-485; 2-wire half duplex with echo, RS-485; 2-wire half duplex without echo. For more details on product, Please refer to http://www.papyrus.co.il/4-port_rs-232_422_485_usb-to-serial_metal_din.htm