Model BB-USPTL4 is an USB to one port RS-422/485 converters. Supporting 2-wire RS-485 or 4-wire RS-422/485 communications, these devices are great for applications requiring long range or multi-drop capabilities. This model uses pluggable terminal blocks on the RS-422/485 side. Two LEDs indicate data transmit or receive. The BB-USPTL4 draws power from the USB port so no power supply is required. Simply install the drivers supplied on CD ROM and plug the converter into an available USB port on your computer or USB hub. The device show ups as an additional COM port in the Windows Device Manager, and is compatible with Windows applications.