Both serial ports and parallel ports are examples of computer technology that were once cutting edge, but now have been replaced by newer methods of transferring data from hard drives to ancillary devices. However, there are many personal computers and other devices in use today that make use of a serial port, a parallel port, or both. The difference between the serial and parallel port is not always understood, owing to the similar design of both ports. Here is some background on each type of port and what they were designed to accomplish.

Of the two, the parallel port is the older port design. The first use of a parallel port was in the early 1970’s and allowed printers to be hooked directly into a mainframe and print orders carried out by entering a section of code through the command station. The parallel port allowed for a one way transmission of data from the source to the printer.

As the personal computer came into common use, the parallel port remained a popular option for attaching a printer to the hard drive of the system. In some circles, the port became commonly known as the printer port, since that function was the most common application of the device. Some manufacturers would go as far as customizing the design of the parallel port so that only certain types of printers could be used with certain brands of personal computers. However, by the mid 1990’s, the parallel ports on most personal computers had been standardized to accommodate just about any make and model of printer.

In addition, the parallel printer became somewhat more functional, in that the design was used to provide one way communication between the hard drive and a number of ancillary devices. Early external modems and storage devices are a couple examples of the broader use of parallel ports. However, since the beginning of the 21st century, the parallel port has largely been replaced by the USB port, although some ancillary devices still allow for connection by both means.

One key difference between a serial and parallel port is that the serial port allows for data to be transferred in from a remote device or transferred out from the hard drive to a remote device. This two-way communication process makes it possible to connect work stations to larger terminals as well as a wide range of peripheral devices.

For most of the history of personal computers, both the serial and parallel port were the most common means of data transfer and communication. However, with both the serial and parallel port replaced by the use of USB ports, fewer new devices are designed to include either a serial or parallel port. Older personal computers that feature a serial and parallel port often require an adapter cable in order to make use of the latest generation of peripheral devices.