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What's on the Outside of your Computer?

The outside of your computer houses the ports that you plus external things into, such as speakers, mice, etc... In addition, the drives that allow you play or burn a CD are visible. Below is a photo of a typical computer exterior:

Item Number
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Item Name Item Description Item Number
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Item Name Item Description
1 PS/2 Ports You plug your keyboard and mouse into these. PS/2 ports were created by IBM for basic input/output. It's important to remember that each PS/2 port is keyed for either a keyboard or a mouse, so you have to ensure you plug the right device into the right port. To make this easier, PS/2 ports are usually color coded. Purple is for your keyboard, and green is for your mouse. 2 USB ports USB ports became standard on most PCs about 5 years ago. There are two current USB specs, 1.1 and 2.0. 2.0 is much faster than 1.1 (1.5 Mbs v. 480 Mbs!), but is fairly recent. USB 2.0 is completely backwards-compatible with 1.1, meaning any 2.0 device will also work in a USB 1.1 port (just at the lower speed) and vice versa. USB is hot-swappable, meaning you can plug new devices in, and unplug devices, while your computer is still on. It is possible, through hubs, to place up to 127 devices on a single USGB device. You can plus almost anything into USB ports: mice, keyboards, cameras, scanners, speaker, etc...) Eventually, USB ports will replace all PS/2, serial, and parallel ports on your computer.
3 Serial ports (9 pin) Serial ports transmit one-bit of information at a time to a device that's plugged into them. What devices do you plug into them? Mice, modems, etc. have all used serial connections in the past. However, serial ports are quickly dying out to make room for the far superior USB port. As an aside, serial ports are also know as RS-232 (the standard that defines what information travels through each pin) and have been known to come in a 25 pin variety, as well as the 9-pin ones shown here. Most modern computers only use the 9-pin variations. 4 Parallel port (25 pin) Parallel ports have 25 pins, and transmit information one byte at a time. Printers, older web cameras, and scanners tend to use this port. However, like serial, parallel ports are quickly being replaced with USB ports.
5 Onboard sound card This allows you play sound from your computer, as well as record into your computer. Speakers, microphones, and other audio equipment plug into the jacks shown here. The larger, 15-pin port allows you to plug older joysticks into your computer. It also allows you to plus in electric keyboards and such (using an interface known as MIDI) so you can use your computer as a recording studio. 6 Video card Video cards allow you to plug a monitor or LCD display to your computer. The smaller 15 pin connector is for older analog monitors, while the larger, white connector (DVI connector) is for newer, all digital flatscreen LCD displays. Video cards handle the display of every pixel on your monitor. In addition, newer video cards accelerate 3-D games, allowing the video card to do some things that the main computer process had to do in the past.
7 56kbs Modem 56kbs modems allow you to dial in to the internet. You use it to dial a phone number from your computer that creates a connection to an internet service provider (ISP) that will then handle your time on the net. 56kbs modems know as v.90 (or v.92). These standards mean that you can use your modem to connect to any ISP that follows the standard. Without them, you might need to buy a new modem when you switch from AOL to MSN! The reason there are two phone connectors (RJ-11, technically speaking) is because the modem allows daisy chaining of phone equipment. So, for example, you can pug your telephone into your modem, so you don't have to worry about getting a second phone jack. 8 TV Tuner Card This card allows you watch television on your computer, as well as record these television shows. It has a connection for the antenna (or cable or satellite system) and an audio jack. You connect the audio jack with a cable that goes into your sound card. This allows you to hear the television.
9 Ethernet Card An ethernet card allows you to connect your computer to a network. It also allows you to connect your computer to fast broadband Internet connections (such as cable or DSL). There are two major, current standards for ethernet, 10baseT and 100baseT. 10baseT can send information at 10Mbs, while 100baseT can transmit at 100Mbs. There is a lot more to ethernet than just this paragraph, but it is beyond the scope of this web page. For more information, you can visit: www.howstuffworks.com. 10 Sound Card This allows you play sound from your computer, as well as record into your computer. Speakers, microphones, and other audio equipment plug into the jacks shown here. The odd shaped connector at the far right is a firewire port (or IEEE 1394). This port is a very fast connection (400 Mbs) that is commonly used in digital video recorders to transfer video to the computer for editing. You may notice that this is the second sound card. This is because the first sound card is integrated onto the motherboard. Usually, sound cards that are integrated (as in built onto) the motherboard do not provide the features or the sound quality of an add-on sound card. For more information on motherboards, see the "inside" portion of this website.
11 USB card These are just two more additional USB ports. 12 CD-RW Drive This optical drive reads CDs (so you can install software and play music CDs). However, it also allows you to create (or write) your own CDs. These drives are rated in three numbers. For example, the drive pictured is rated as being a 48X/12X/48X drive. Each "X" translates to 150kbs. The first number represent how fast the drive can write to CD-R discs. These discs you can only write to once. If something goes wrong, or the data changes, you have to throw away the disc. The second number represents the drives speed when writing to CD-RW discs. These discs can be deleted and reused up to a 1000 times. The final number represents how fast the drive can read discs. So, for example, this drive can write CD-R discs at 150kbs * 48 = 7200 kbs.
13 DVD Drive This drive allows you use CDs and DVDs in your computer. DVDs look just like CDs, except where a CD can hold 750 MB of data, a DVD can hold over 4 GB of data! This allows full detail movies to be placed on a DVD disc. With a DVD drive, you can actually watch these DVD movies on your computer! Also, some (albeit not many) software applications come on DVD. This type of drive allows you use that software. 14 3.5" Floppy Drive This is a standard 3.5" floppy drive. It will allow you to read and write 1.44 MB 3.5" floppy discs that have become so ubiquitous.

Created by: Russell O'Neill (roneill@gmu.edu)