When a byte is received over serial, the individual bits are set on the individual digital lines connected to the printer’s parallel port. At this point, the strobe line is pulled low ...

Old Macs used the serial port for printers. Also known as an RS-232 port, serial ports provide very slow speeds and have been superseded by USB on desktop computers. USB-to-serial adapters are ...

Because there was only one serial and one parallel port on the computer, the key acted as a pass-through so that other keys and peripheral devices could connect. In fact, the nickname "dongle" was ...