[FTDI 232RNL Chip]It uses the FTDI 232RNL chip which has higher stability and wide compatibilit,which is enough to handle various complex application scenarios. | [USB to RJ12/11 Cable] This is a 6P4C cable,It leads to 4 signals: GND, Tx, RX, GND.It can be used in RJ12 interface which uses 6 data lines and RJ11 interface which uses 4 data lines. | [Applicable Devices] The USB RJ11/12 adapter is a replacement for APC part number 940-0144A.Applicable Models: AP77XX, 78XX, 79XX, 86XX, 88XX, 89XX. Or UPS, ATS, and other devices that support RS232 RJ12/11. | [Easy to use] Plug and play, no need to install drivers.support Windows 7, 8, 10, 11, Linux OS and Mac OS operating systems, if you can not automatically install the driver, please go to the FTDI website to download the appropriate chip driver. | [Buyer Support]Jhoinrch backs this usb a to RJ11/12 with lifetime technical support, a one-year product replacement and warranty, and a 100% customer satisfaction guarantee.