Cables, Connectors, and Ports
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 are used for many devices, but especially for mice, keyboards, and external storage drives (HDD, DVD, etc.).
Today, there are two main cable types: USB (Universal Serial Bus) and FireWire (alternately called "1394" on PCs). However, USB has become much more popular, and FireWire is dying out.
[Hi-speed USB (2.0), Superspeed USB (3.0)]
|The cable type below, Firewire, is mostly discontinued, but is still found on many computers.|
Firewire B (FireWire 800):
Firewire S1600 and S3200:
There are a large number of "mini" connectors for USB and other cable types. The more common USB connectors are:
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:
connect to a monitor/ HDTV
|HDMI||A new, high-speed video connector used with HDTVs. Recently, computers have included these. Has built-in DRM copy-protection. Carries audio and video.|
|DisplayPort||Similar to HDMI, it can carry audio and video and has DRM copy protection. However, DisplayPort is cheaper. Part of the new Thunderbolt technology.|
|DVI||Digital connector, designed for better use with LCD monitors. It is capable of carrying an audio signal, but usually does not.|
|VGA||Most common video monitor cable/port used for computers. Designed for CRTs, but can be used with LCDs. Carries video only.|
connect to an old analog TV
|RCA||Audio/Video combination. Yellow is video, red is right-audio, white is left-audio.|
|S-Video||Video only (no audio). This is most common type of TV-out port on computers.|
|Audio||Audio||Used for mono/stereo audio. Most computers use this jack.|
Right now we are in a transition, from old analog "NTSC" TVs to higher-resolution digital HDTVs. The old RCA and S-Video cables will disappear over time as old TV sets are discarded.
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.
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)|
Each computer has one Ethernet port. Two computers can be connected directly, with only a cable. Three or more computers require a hub (a device to connect multiple devices) to be used. Using a hub is usually very simple. Just connect the computers to the hub with Ethernet cables; the rest is automatic.
More will be explained about networks in the unit on operating systems.
There are a wide variety of cables, and it would be impossible to review them all quickly. However, here are a few more cable types that you might encounter on your computer:
|Thunderbolt||Now found mostly on new Macintosh computers, Thunderbolt is a recently-released high-speed peripheral cable. This cable is able to connect to a variety of devices, including video, network, and storage devices; the idea is to consolidate cables into just one, instead of having several different cables connected to the PC.|
|S/PDIF||S/PDIF (Sony/Philips Digital Interconnect Format) is a special audio connector; instead of plugging in several cables, you can use this one cable (either co-axial or optical) for home-theater sound output.|
|PC Audio ports||
On Windows PCs, especially on the rear panel of desktop machines, audio ports are often color-coded. While some may only have two audio ports (line out / speaker-headphones, and line-in / microphone), some have three to six, and these can be used for home theater sound systems. Very simply, the colors represent:
|LEGACY PORTS (ports which are old and often not used any more)|
|PS/2||PS/2 ports were used for mice and keyboards. This is perhaps the most common legacy port; it can still be found on most desktop computers. It is a very low-speed "serial" connector, which works fine with keyboards and mice, because they do not transmit much data and do not require high-speed connectors. Although any PS/2 device can be used with a PS/2 port, color-coding usually indicated that purple ports are for keyboards, green ports are for mice, and both colors together can be used for either.|
|Parallel||Parallel cables were often used with printers, and may still be on some devices to allow the use of very old printer devices used by some people or companies. It is becoming more uncommon, perhaps due to the fact that its large size takes up too much room on a motherboard.|