When speaking of computer ports, two different things can be referred to. It can mean the hardware port which serves as a physical connection for a computer and its peripheral devices, or it can mean the logical or data connection used by programs or networking processes to exchange data directly.
- Hardware ports. These physical connectors facilitate communication and data transfer between a computer and an external hardware device. Their chief advantage is that it allows for the easy replacement of external devices. For example when a keyboard, mouse or monitor malfunctions, one can simply unplug it and substitute a working model with compatible specifications. There are generally three types of external ports on a computer: serial, parallel and USB. Serial ports can be short or circular as in those sockets behind the PC where the mouse and keyboard connects. They are called thus because of the way they transmit data which is 1 byte at a time or in series. Parallel ports on the other hand can be short or long rectangular sockets. This is where most old printers connect. They are faster in transmitting data than serial ports because they send the 8 bits of a byte of data in parallel rather than in a series. Thus a parallel connector would need 8 wires while a serial connector would only need one. Finally there is the Universal Serial Bus or USB port. This is one of the latest designs in external computer ports and has replaced most serial and parallel ports. Keyboards, mouse, printers, scanners, webcams, flash drives and other devices now have USB connectors. It is flat and rectangular and can be found at the back and/or in front of a computer. The goal of USB is to be the standardized connector for most peripheral devices.
- Logical ports. Internet protocols are a set of standards or rules that govern data communication in a computer network. All protocols and their associated processes each use a specific port. These ports are numerically identified from 0 to 65535. These identification numbers are standardized by the group called Internet Assigned Numbers Authority (IANA) so that they are globally recognized and used. For example, servers that send email use Simple Mail Transfer Protocol (SMTP) which is handled by a particular server process. This process is associated with the right data through the assigned port which is port 25. Ports numbered from 0 to 1023 are labeled Well-Known Ports because they have been associated for many years with standard services such as email (SMTP) and web browsing (Hypertext Transfer Protocol or HTTP). Ports numbered 1024 and above are not consistently associated with common network processes and are labeled as Registered Ports.
Virtual or physical, computer ports are essentially intersection points where either two or more devices or programs can exchange data. Knowing a little about them can help regular users maintain and troubleshoot their systems' hardware and/or network security.