Cables and connectors

October 2017


In information science, connectors, normally called "input-output connectors" (or I/O for short), are interfaces for linking devices by using cables. They generally have a male end with pins protruding from it. This plug is meant to be inserted into a female part (also called a socket), which includes holes for accommodating the pins. However, there are "hermaphroditic" plugs which can act as either male or female plugs, and can be inserted into either one.

Pin layout

The pins and holes in connectors are usually linked to the electric wires which form the cable. The pin layout describes which pins couple with which wires.

Each numbered pin generally corresponds to a wire within the cable, but sometimes one of the pins is left unused. Additionally, in some cases, two pins may be linked to one another; this is called a "bridge."

Input/output connectors

The computer's motherboard has a certain number of input-ouput connectors located on the "rear panel."

Connectors on the rear panel

Most motherboards have the following connectors:

  • Serial port, which uses a DB9 connector, for connecting older devices;
  • Parallel port, which uses a DB25 connector, mainly for connecting old printers; 
  • USB ports (1.1, low-speed, or 2.0, high-speed), for connecting more recent peripherals;
  • RJ45 connector (called the LAN port or Ethernet port), for connecting the computer to a network. It interfaces with a network card built into the motheboard;
  • VGA connector (called SUB-D15), used for hooking up a monitor. This connector interfaces with the built-in graphics card;
  • Jacks (Line-In, Line-Out and microphone), for connecting speakers or a hi-fi sound system, as well as a microphone. This connector interfaces with the built-in sound card.


Cables y conectores
Cables y conectores
Cabos e conectores na informática
Cabos e conectores na informática
Latest update on October 16, 2008 at 09:43 AM by Jeff.
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