This device can be used to connect a teletypewriter via USB.
It provides 40mA to control the 'Magnet' of a TTY.
Also it can receive input from the TTY. The interface can be used Half-Duplex (as it was used in the old day) and evern Full-Duplex to allow the PC decide what characters to return.
Also required is a 48 Volts power supply and a CP210x USB interface.
The USB interface must be re-programmed to run at 50 Baud whenever 300 Baud is selected. *TBD*
Download the schematics below.
Eagle schematics V1