What are all these Ports?

Posted By BrokenClaw on September 15, 2007

A port on a computer is a socket for a specific type of plug, used to connect components or peripheral devices. On early models of computers, each peripheral device had its own port: an AT keyboard port, a serial port for a mouse or modem, a parallel port for a printer, a video port for the monitor, etc. PS2-USBWhen IBM introduced their PS/2 line of PCs in 1987, they created new, more compact, ports for the keyboard and mouse. The PS/2 keyboard connector and the PS/2 mouse connectors, usually color-coded purple and green, remained standards for computer manufacturers for many years. The photo here shows a converter for using PS/2 connectors to a USB port (see below). With regard to computer monitors, the VGA (video graphics array) video port, which was introduced in that same year, is still the standard in PCs.

The term port has several meanings in the technology realm. It is also used to describe a virtual pathway set up by the CPU to connect data sources, such as Internet traffic that runs through port 80. It is also used to describe the process of re-coding software to run on a different platform, such as porting a video game from the PC to the Sony Playstation®. Those topics are not discussed in this article.

When audio became a standard feature of the PC, the industry simply used the same ports that were already in use in portable stereo equipment. To this day, PCs still use the standard 1/8th inch mini plug for connecting speakers and microphones.

A major improvement in standardizing connectivity among computer devices was the development in the 1990s of the USB (universal serial bus) port. The USB port became an immediate success with manufacturers and consumers for several reasons:

  • it is a standard port which can be used for a variety of peripherals (excluding monitors), such as keyboards, pointing devices, printers, webcams, scanners, digital cameras, external hard drives, etc.
  • devices can be connected while the computer is running, on-the-fly, without requiring the computer to be rebooted.
  • USB ports can be piggybacked or split to make more ports, which can be useful for laptop computers.

Another feature of USB ports is their ability to provide low-level power beyond the normal data transfer. USB-1394While not enough to power major devices like printers, they opened the way for things like scanners and programmable keyboads. It wasn’t long before computer manufacturers recognized the convenience of having USB ports on the front of computers for a variety of computer toys, such as LED lights, beverage warmers and coolers, business card readers, etc. In recent years, the USB flash drive has become ubiquitous.

The photo above shows two USB ports on the right, and an IEEE1394 port on the left. This port is also known as FireWire® and iLink®.

FireWire is another port intended for audio and video transfer. As its name implies, its main advantage is high transfer speeds. FireWire was developed for Apple computers more than a decade ago, but its adoption as a standard port in low-end PCs has been slow. On non-Apple devices, the port is known by its specification IEEE1394. However, for most users, USB version 2 is an acceptable alternative to FireWire. Nevertheless, FireWire is a useful upgrade for home users who want to move video from their digital video camera, or play recorded TV shows and movies from their computer on their digital flat screen television.

VGA is still the standard port for most home computer monitors. High-end computers can also use the digital video interface, abbreviated DVI, which is designed to take advantage of the enhanced qualities of flat screen monitors. DVI is also better equipped to connect directly with digital television displays. More recently, premium computers are being equipped with HDMI (high-definition multimedia interface) ports as well. HDMI was designed for high-definition video, so its only useful if your computer has the ability to play high-def video — either downloaded from the Internet or from a Blu-ray disk — and you have a high-def television.

The last type of port on a computer is for networking. When phone modems became commonplace, manufacturers began to put the modem inside the computer as part of the normal hardware. Phone-Ethernet portA phone port on a computer is the same as the telephone jack on the wall or on a phone. In the US it is known as RJ11.

For a wired home network connection, it’s necessary to have an Ethernet port. Ethernet cables come in a variety of styles, but the most common is called Category 5e, or simply Cat 5e. The connector, and the port, resemble a phone jack, but they are slightly wider. In this photo, the phone port is on the left and the Ethernet port is on the right. Ethernet is typically used in the home to connect a broadband router to the main computer.

Routers can have several Ethernet ports for connecting multiple computers, although Wi-Fi is now the norm for connecting additional computers over short distances in the home.

Ethernet transfer speeds are described in terms of megabits per second, or Mps. The most common in home networks today is 100 Mps, but 1000 Mps, known as Gigabit Ethernet, is available when combined with compatible hardware.


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