This device was designed as a quick to use support tool in my workshop.
The converter allows two simultaneous RS232 connections with variable voltage levels (can be switched between 3.3V and 5V). Individual serial buses can be turned off with a switch to easily distinguish each COM port. As this is a prototyping tool, serial connections are made with small wire hooks. The device works off a single USB-C port and includes status LEDs.
Design is based around two FTDI FT232RL chips, that are internally connected to a basic USB2.0 HUB IC. Each FTDI chip can be artificially unplugged from the hub via a switch. Power is fed straitght through the USB-C port.