GDA-HLU1 is a USB-to-RS485 adapter(automatic data direction control) for all Gicren's standard devices, whose conversion mechanism is "USB UART(FT232RL) RS485(SP485EEN)", so it can also be used for other general purpose via pin header, such as “USBUART”, “USBRS485” and ”UARTRS485”Features： Taking into account security issues, there are only D+ and D- pins connected to SP485EEN. In other words, the front-end circuit and back-end circuit do not share the same ground in the printed circuit board, but it is recommended to connect them manually to avoid excessive common-mode voltage when you are sure the connection is correct. In addition, the onboard high-quality D-Sub-9Pin-Female, SMT-PH2.0-9Pin, Header-2.54mm-Pitch-9Pin, fuse and selectable matching resistor make this adapter more flexible and reliable. Visit here for updated documents of Gicren’s products