Enter the isolated USB null-modem. The device consists of two USB Communication Device Class, or CDC chips, creating a USB serial port for each attached computer.

The null modem is a method of communication originally developed to allow two pieces of data terminal equipment (DTE) to be connected closely together using RS232 serial cable. Null modems are ...

Rather than deal with cables and wired adapters, [g3gg0] decided to design a wireless adapter with WiFi and Bluetooth on one end, and true RS-232 on the other.