IIRC, while the VT-220 had both 9-pin and 25-pin RS-232 ports, the 9-pin port was used to attach a printer. You also typically need a "null modem" adapter or ca

IIRC, while the VT-220 had both 9-pin and 25-pin RS-232 ports, the 9-pin port was used to attach a printer. You also typically need a "null modem" adapter or cable to connect a terminal directly to a PC serial port (or USB serial adapter). There's lots of original documentation for DEC VT series terminals here[1]. [1] http://www.vt100.net/ http://www.vt100.net/