Computer & Networking Cables

common cables

Cables connect computer components and devices, allowing them to communicate with each other. As of 2010, computing applications employ hundreds of different types of cables, many of them specialized and rarely used, while some are common. Computing cables of the same type also come in various lengths depending on the application.

Internal cables

SATA cable

You might never see or deal with cables that are inside a computer, connecting the internal components. Internal power cords supply the motherboard, disk drives and expansion cards. SATA and/or IDE cables allow hard drives and optical drives to communicate with the system. Newer machines may have dual video cards, and a special "bridge" cable connects these so they can work together. A laptop contains miniature versions of many of these cables.

Input / output

USB printer cable

Computers need a way to communicate with the people using them, and input / output (I/O) devices accomplish this. Input devices such as mice and keyboards allow you to tell the computer what to do. Cables that connect these devices to the computer are often PS/2 or USB cables. Output devices like monitors display information for you, and a video cable connects the display to the computer. Printers are another common output device, and they often use a USB or parallel cable to transfer data.

Networking

Cat-5

Computers communicate with each other via network cables. While the advent of wireless networking technology has reduced the need for physical cables, they are still widely used. Cat-5, also known as Ethernet, is the most common network cable in use today. Fiber-optic cables network computers over long distances and at great speed. Fiber-optic cabling forms much of the backbone of the Internet and connects the continents along the ocean floors.

Common issues

Twisted pairs in Cat-5

Computer cables are susceptible to several types of electrical interference that limit the length of the cable that can be used. For instance a single Cat-5 cable contains smaller wires inside that transfer data back and forth simultaneously. These wire are twisted together in pairs to reduce crosstalk between the wires and also electromagnetic interference (EMI) from things like external power lines and electric motors. Foil shielding also reduces EMI, but Cat-5 is often unshielded. Cat-5 is rated for a maximum distance of 100 meters. Other types of cables may have different ratings.

Adapters

DVI to VGA adapter

If you do not have the right cable, you can sometimes avoid replacing the entire cable by using an adapter. Monitors are a good example. Many newer monitors come with a DVI or HDMI cable, while older computers have a VGA video port. An adapter allows you to connect your old computer to the newer monitor hardware. Another common adapter lets you connect an older PS/2 keyboard or mouse to a computer that only has a USB port. Computer standards and cabling are always evolving, and adapters bridge the gap between older and newer technologies.

References

• University of South Florida: Network Cabling
• The Guardian: Submarine Cable Map
• Skepticfiles: Quick Guide to Computer Cables