Computer Cases

Computer Cases

There are two basic styles of cases the computer may come assembled in. They are basically tower and desktop style cases. Desktop style is in the shape of a rectangular box, that sets flat on a desk. Usually the computer monitor is placed on top of it. A tower case, looks similar to a tower as the name says. These computers will be placed off to the side of the keyboard and monitor. The tower case is the most popular style of desktop computer today. It is also recommended by some microprocessor manufacturers since it can be designed for better heat dissipation. Tower cases come in several sizes which are:

• Mini-tower - The smallest.
• Mid-tower - The standard size, recommended for most applications including standard desktop systems and some servers.
• Full-tower - The largest. Usually this is a very tall case and you may have a difficult time fitting it where overhead is limited. This case is usually used for high powered servers.

Looking at the front of your computer, you see the front panel:

The exact locations of many of these items vary somewhat from computer to computer, but the overall layout is generally the same. Types of cases come to fit AT and ATX sizes. If you want a modern computer, you will want, or should have an ATX case. The AT or ATX version refers to the type of motherboard the case is designed to fit. The AT case is for the old type of motherboards such as for the 80486 microprocessor based computers.

Definitions

• Pin - A part of a connector that extends outward to extend into and make contact with a socket. Referred to as the male side of a connector.
• Socket - a part of a connector that contains an internal contact to receive the extended side (pin) of a connector. Referred to as the female side of a connector.
• Jack - A receptacle where power of signal connectors may be plugged into. These are usually on the case of a computer or the motherboard and are made to receive plugs from devices such as keyboards.
• Plug - The part that connects with the jack, which comes from a keyboard, mouse, monitor or other device. This is the side associated with a cable.

The Back Panel

The back panel includes two power connectors. One is to connect your computer to the wall outlet, and the other can be used to connect the monitor power to operate from the socket on the back of the case. Usually the power connector for the monitor is not used since many use a power strip or a surge protector to control the power to all devices.

The keyboard and mouse connectors are both normally PS2 connectors on new computers. There are two sizes of PS2 connectors, Normally with today's equipment you will want the smaller PS2 connector on your keyboard. Mice don't come with the larger PS2 connector. There are adapters made to allow smaller connectors to adjust to a larger sockets and vice-versa. A PS2 connector is a round connector with 6 pins and a plastic key. The keyboard always uses the PS2 connector, however the mouse may be a serial mouse and may plug into the serial cable on your computer. With modern computers, normally a PS2 mouse will be used.

Near the keyboard and mouse connectors is normally a connector for a parallel printer. This is what is called a parallel device, meaning that more than one line carries data in one direction at a time. This is the connector you will plug your parallel printer into. See your computers motherboard or owner's manual for exact placement of these connectors.

Usually a little below the parallel printer connector are two serial connectors. There are two types of serial connectors, which are called DB9 and DB25. One type, DB9 contains 9 pins or sockets and the other contains 25 pins or sockets. You may have any combination of the 9 or 25 pin connectors. Also some are female style connectors, and others are male. You will need to make sure your connectors match for their given types. The serial cables are normally used to connect a serial mouse, an external modem, or some other device to your computer.

Below the parallel and serial connectors are a series of slots which are covered by a metal plate. This is where additional cards are plugged into your system. These cards are usually a video card, a sound card, internal modem, and one or more network cards. Your monitor connector would plug into a connector on your video card, and your speakers will plug into a connector on your sound card. See your sound card and video card manual for exact placement of these connectors on the card. These cards are plugged into the motherboard and you must open your case up to remove or add one of these cards.