TXD Light: White, for RS232 Data Transmission Indicator Light, Data : USB->for RS232. RXD Light: White, for RS232 Data Reception Indicator Light, Data : for RS232->USB. Safety: The for RS232 end includes RXD, TXD, RTS, and CTS pins with built in overcurrent guard and ESD guard circuits, enhancing the safety and longevity of the device during operation.
eBay