Why are serial ports used almost exclusively now when one would have thought you could get more data down a parallel port quicker?
Serial ports are used to connect to serial interfaces, and were standard on early computers for connecting a modem, mouse, and other peripherals. Old Macs used the serial port for printers. [1] Serial ports provide a serial communication using one line, and thus have no dependency on other wire's speed. [2] Parallel ports provide an interface to connect multiple lines to prepare a parallel communication to send large data at a time. [3] While parallel ports send data by sending multiple bits in parallel fashion, serial ports send data bit by bit after sending a bit at a time. [4] Serial ports are able to transmit a single stream of data at a time, while parallel ports are able to transmit multiple data streams at a time. [5]
Serial ports are still used in industrial settings because they are easy to use and do not require custom drivers. Most operating systems provide native support for serial interfaces. [2] Serial communication is a communication established via serial interfaces which transmit data over one wire one bit at a time. As a comparison, parallel ports transfer all the 8 bits of a byte in parallel, all in one go, over a cable with 8 wires. Hence, a parallel port transmits data faster while a serial port is used for communications with relatively slow data rates. At the same time, the price and size of the cable used in a serial communication are real advantages of a serial port connection. [1]