Your friend is mistaken. This serial port he is talking about is called "CGA" and closely resembles a serial port. However it still requires a graphics card and a monitor! You can convert a CGA signal ...
If you've been using computers for more than a couple of decades, you've probably used a serial port to attach peripherals like your mouse and modem. Until the USB standard rendered them obsolete in ...
Serial ports were dropped before parallel ports were - my old R52 has a parallel port but not a serial port. A quick look at that list shows that the last Thinkpads that had the ports were the A31 and ...