Review on Gearmo 4-Port USB to Serial RS232 Adapter with FTDI Chipset, Compatible with Windows 10, 8, 7, XP, Linux, Mac - Enhanced ESD and Surge Protection by John Patterson

Plugged it in and the Linux kernel recognized it with no problems. Ports work as expected. I wrote udev rules that are triggered by the cable serial number so that there are predictable /dev symlinks for these four ports no matter what other USB serial devices are connected. Kudos to Gearmo and SerialStuff for a detailed and accurate product description that actually mentions Linux and the specific FTDI chipset used. The rx/tx LEDs seem fine - it would be even better if there were rx/tx LEDs for each port, but for $40, can't complain.