On Linux, the device may appear as /dev/ttyUSB0 but be inaccessible to non-root users. sudo chmod 666 /dev/ttyUSB0 (temporary) or add your user to the dialout group: sudo usermod -a -G dialout $USER .
Never download drivers from third-party file sharing sites. Instead: asr9xxusbconsoledriverszip
The file asr9xxusbconsoledrivers.zip is a compressed archive containing the official drivers for the Silicon Labs CP210x series of USB-to-UART bridges. Cisco uses this specific chipset inside the console ports of the ASR 900 series routers, as well as many other platforms like the ISR 4000 series. On Linux, the device may appear as /dev/ttyUSB0
The ASR9xx USB Console Driver offers several key features and benefits: Instead: The file asr9xxusbconsoledrivers
While Cisco provides drivers for Linux and macOS, the majority of field engineers and network admins use Windows laptops. Here is the definitive procedure for installing asr9xxusbconsoledrivers.zip .