Cables
The previous chapters detail the hardware found in the computer case. A great deal of additional hardware can be used by attaching them to the computer using cables. These devices are called peripherals.
In English, the word "peripheral" means something on the edge, or very close outside.
Since peripherals are outside the motherboard and case, they must be connected using a computer peripheral cable.
You may heave heard their names, but you may not know what they are: USB, VGA, 1394, Ethernet, and so on. You may have noticed that there are several strange plugs in the sides or back of your computer, and you don't know what they are for. Knowing which cables to use can be important. For example, if you have a laptop, your computer can probably plug in to your TV and use it as an extra monitor.
The Spaghetti Behind Your Desktop
There are several kinds of cables you can use with your computer. Each cable type can be used for different purposes. To use a cable, your computer must have a port (a hole, or socket, which the cable goes into) for that cable. Some computers have many cable ports, other computers only have a basic few. It may be important to know which ports your computer has.
The part of the cable you plug into devices is called a connector (sometimes also a "jack" or a "plug").
Categories of Cables
There are several categories of cables, including:
- Peripheral cables: used to connect computers to external devices like printers, mice, hard drives, etc.
- Audio/Video cables: used to connect computers to computer monitors, TVs, microphones and speakers
- Network cables: used to connect 2 or more computers together in a network
There are a few other categories which we will not focus on. One is "legacy" cables and ports, which refer to old cables and ports which are not used any more. These include serial, PS/2, parallel, and SCSI cables. You do not need to know them, although you may sometimes find them on your computer (especially desktop computers). Some computers still have them so you can continue to use older peripherals.
Peripheral Cables
Peripheral cables are used for many devices, but especially for mice, keyboards, and external storage drives (HDD, DVD, etc.).
Today, the dominant cable type is USB (Universal Serial Bus).
USB 1.0
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USB 2.0
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Connectors: 
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Ports: 
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Type B (peripheral) Connectors: 
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Ports: 
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Mini-B & Micro-B Connectors: 
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Ports: 
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USB 3
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Connectors: 
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Ports: 
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USB3 Type B (peripheral) Connectors: 
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Ports: 
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USB3 Micro-B Connectors: 
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Ports: 
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USB 3.1 — Type C
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Connectors: 
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Ports: 
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Never Works on the First Try
Isn't this just so true?
There is one way to plug in a USB cable the right way on the first try: look at the connector for a logo. The logo, which is always on a specific side of the connector, usually goes up. However, this does not always help, as some USB ports are sideways. In such a case, if you use the port often, you can try to remember which side it "up."
There is another way, however: a new type of cable becoming available: reversible USB. This allows you to plug in a USB cable correctly on the first try.
The new USB 3.1 Type C connector (pictured previously on the page) is also reversible, but has not yet been widely used.
Audio / Video Cables
You computer can connect to a variety of audio and video devices. Using the audio connectors (usually just a standard audio cable like you use every day), you can attach microphones, speakers, and other audio equipment. The video ports, however, are mostly just for sending video out to a TV or an extra monitor. It is possible to get video into the computer, but usually that requires a peripheral cable.
Here are the standard video and audio cables:
| Type | Name | Connector | Port | Description |
| Video: connect to a monitor/ HDTV |
HDMI |  |
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A high-speed video connector used with HDTVs. These are the most popular video cable. Recently, many computers include these. It has built-in DRM copy-protection. Carries audio and video. |
| DisplayPort |  |
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Similar to HDMI, it can carry audio and video and has DRM copy protection. However, DisplayPort is cheaper. It is the basis of the new Thunderbolt technology. However, it is not very widely used. | |
| DVI |
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Digital connector, designed for better use with LCD monitors. It is capable of carrying an audio signal, but usually does not. | |
| VGA |
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Most common video monitor cable/port used for computers. Designed for CRTs, but can be used with LCDs. Carries video only. | |
| Audio | Audio |  |
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Used for mono/stereo audio. Most computers use this jack. Famously, Apple did not include it on the iPhone 7. |
The transition from old analog "NTSC" TVs to higher-resolution digital HDTVs concluded some time ago. The old S-Video cables will disappear over time as old TV sets are discarded, although use of the Composite/RCA cables continues.
You should become familiar with what cable ports are on your computer. Depending on what ports your computer has, you can connect with a variety of displays and TVs. The ports will also tell you what kind of cables you will need to buy.
Many times, your computer's ports will not match the ports on a cable or TV. Usually, this can be fixed with an adaptor—a cable which has one type of connector at one end, and a different type of connector at the other end. For example, there are cables which have an HDMI port on one end, and a DisplayPort connector on the other, as seen below.
Network Cables
Computers are able to connect together in groups so they can communicate. This is called a "network." When they are connected together in the same location, the network is called a LAN (Local Area Network). The cables used to connect the computers in a network are called Ethernet cables. However, because Ethernet is universal, these cables are also called LAN cables and network cables.
Computers can be also connected in a LAN without wires.
Ethernet cables are very similar to normal telephone cables, except they have 8 wires inside instead of 4. Ethernet cables are also called LAN cables or Network cables. Below are images of Ethernet cables (at left), and telephone cables (at right) for comparison.
| Ethernet / LAN / Network | Telephone (not LAN) | ||
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| connector | port | connector | port |
Each computer has one Ethernet port. Two computers can be connected directly, with only a cable. Three or more computers require a hub or a switch (a device to connect multiple devices) to be used. Using a switch is usually very simple. Just connect the computers to the switch with Ethernet cables; the rest is automatic.
More will be explained about networks in the unit on operating systems.