ITEM NAME:USB 2.0 To RS485/RS422 Serial Converter Adapter For Win7/ Win8 Features: USB to RS485 Converter Adapter USB connector: to your PC RS485 connector: to your RS485 device No need external power,.RS485 connector: to your RS485 device. USB to RS485 Converter Adapter. 1x USB to RS485 Converter Adapter. USB connector: to your PC. Better than using CH341D chip or similar chip to support the laptop USB port.