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Know your Cables

There are hundreds of different cables and connector types that have come and gone over the years. Computers and the things that connect to them are getting faster and more complex every year. Eventually a cable and connection standard becomes obsolete and must be updated or replaced.

People often wind up with a box full of wires and cables over the years not knowing what they do or if they're even still useful. So in this article, I'll review a bunch of cables and connector types to help you learn what they do and if you still need them.

I'm only reviewing cables that a non-geek consumer might have. For you computer geeks, you know there's a whole 'nother galaxy of obsolete cables that I don't need to go into. Because if you have them then you already know what they do -- you don't need my help.

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Connects your computers and some peripherals (such as printers, Roku, TV sets, Apple TV, etc.) to your internet router and enabling access to the internet. The clear plug on the blue cable has 8 gold contacts. It looks and plugs in just like an oversized telephone plug.

Ethernet cables come in many colors to aid in visual identification when dozens are being used but otherwise color makes no difference. Both ends are exactly the same.

Keep any Ethernet cables you might have. Ethernet has been in common use for 20+ years and is not going away.

ethernet cable


This is a "Super Speed" USB 3 cable. You can see the "SS" symbol molded on the plastic part of the plugs. Most often, it's used to connect portable external hard drives to your computer where high speed is important. Other USB peripherals such as printers, scanners, phones, etc. do not use this connector.

The blue tongue inside the connector means it's a USB 3 cable. Sometimes manufacturers use a black or white tongue, even on USB 3. But you should never see a blue tongue on a USB 2 cable.

These cables are still relevant so you should keep them for the time being. They are slowly becoming obsolete but you've got a few years.



This is a new standard that is (unfortunately only slowly) catching on. A great feature is that it's reversible, meaning it plugs in either way without having to flip it over -- very convenient. Unfortunately it's not backward compatible with earlier USB cables, though adapters are available. 

USB C was designed to be future-proof, meaning the specification includes expansion capabilities that weren't included in earlier USB specs.

You're unlikely to have these cables at this time. But if you do, you definitely want to keep them. Eventually they will replace USB 2 and USB 3 cables, but that's still a ways off.

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This plug is smaller than it looks here. The silver oval is barely over 1/4 inch wide.


This cable has been around since about 2000 or so. 

The flat side (called the Type A connector) plugs into your computer and is always the same. The other end (Type B) plugs into your device and is far from uniform. There are many different shapes for the type B connector, shown as 1, 2, 3, and 4 here. And that's not even all the type B ends out there, just the most common.

The type B (device end) connector # shown in pictures

  1. Mainly used today for connecting larger devices such as printers and scanners to your computer. Virtually all printers and scanners have a USB 2 jack even if they also offer other connection types, such as Ethernet or Wi-Fi. Still in common use.

  2. Used for many smartphones, digital cameras, GPS units, and other small portable devices. This is by far the most popular of the small type B plugs and is still in common use.

  3. An older, once popular plug used for early small portable devices. Rarely used on newer devices today though still somewhat common since these older devices are still around.

  4. Was never widely used and even less so now.

USB 2 is also becoming obsolete, but not just yet. You might want to hold onto any cables that have the Type B #1 and #2 pictured. You only need #3 and #4 if you have a device with this type of jack. Otherwise you can discard these two types.

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Apple-specific USB Cables

Apple has used proprietary connectors for years. One end is a standard Type A USB plug, like the one pictured above, that plugs into and works on any desktop or laptop computer regardless of brand. The other end (pictured here) is Apple proprietary, working only on Apple gadgets.

Lightning: This is Apple's current technology. It's reversible so you'll never have to flip it over to plug it in -- it goes in either way. That's a surprisingly nice feature. Definitely keep these on hand.

30 Pin: This is is Apple's older technology. None of Apple's current lineup of products use this connector and hasn't for some years now. The only reason to keep this cable is if you have an older iPhone, iPad, or iPod device. Otherwise discard them.

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30 Pin (deprecated) and Lightning Plugs

Video Cables

There's a bunch of computer video cables, too. Here's the cables you are most likely to see. Video cables are a little bit harder to get rid of because none of them are ubiquitous. All four of these have the same connector on both ends.

VGA: The oldest and still a common cable for PCs and monitors. Most PC monitors have a VGA jack but some newer computers and TV sets may not. This standard is dying but it's not dead quite yet. Keep these cables for now.

DVI: An older standard but not in common use. Most computers, some monitors, and all TVs and players lack this connector. If you have unused cables like this in a box, you should be ok to discard them.

HDMI: Nearly all newer computers have HDMI jacks that accept this plug. This is rapidly becoming the standard video cable, especially where TVs and player appliances are concerned. Definitely keep any of these you have.

DisplayPort: A little newer than HDMI has but not caught on, at least not with the larger plug pictured here. You probably don't have any of these anyway.

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Various Power Cables

These three power cords will never be obsolete.


Keep any that you have.


Desktop computer, large printers,

other large peripherals

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Laptop charger/power

brick, smaller

Laptop charger/power

brick, larger

Laptop Chargers

Unfortunately, there is no standard for laptop chargers. They have different output voltages, amperages, plug polarity (+/- can be reversed), and the silver tip that plugs into the laptop/device comes in many sizes. Even chargers within a single brand, like Dell, can differ between laptop models. It's annoying as hell that the laptop makers can't agree on something so basic. Just like mobile phones were before USB chargers became commonplace.

Consequently, if you have extra laptop chargers/power bricks like this laying around or other small (usually black) power transformers with silver tips with no associated laptop or device, then it's best to dispose of them. Unless you can read the label and understand all the numbers on it (or have a geek friend that can read it) then it's too unsafe to attempt to use it with a different laptop or other device. You will risk frying the device.

laptop charger.png

RCA Cables

These are used to carry left and right analog audio channels between stereo system components, such as a turntable or tape deck to an amplifier or receiver and perhaps an equalizer. If there's a third cable, yellow usually, then it's intended for carrying analog video to an old-style boxy TV set.


In this case, yellow generally means composite video. They can also be used for three-cable component video, which was the gold standard of video signal interconnect back before digital became popular.

Regardless, it's very unlikely you'll ever use these again. If you have an old-school hi-fi stereo system with actual, physically separate components (not a cheap all-in-one component stack), you might use them. But you'll never use them for TV unless you still have and use a VCR. Barring that, these are safe to discard.

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Coaxial Cable

Used to deliver cable TV and internet service by cable-based providers, such as Comcast and Mediacom. Sometimes connects to the TV itself, but usually connects to a set-top box and your cable modem.


It can also be used to carry video and audio signals from a VCR to your TV set. But this is considered the worst possible way to connect a VCR to a TV. The quality is really bad by today's standards.

This cable is about 3/8 inch in diameter and is quite stiff. Unused cable should be rolled up in a coil about 12 to 18 inches in diameter. Do not bend sharply. If you have a spare coil of coax cable laying around, especially a longer coil, you might want to keep it in case you relocate your TV or cable modem.

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The following cables and any peripheral that uses them are quite likely obsolete today. You can safely discard any of these.

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Serial RS232 cable. Note there are

two rows of pins, not three


Parallel printer cable. Some SCSI cables have a similar connector.


PS2 plugs, most common on very old keyboards and mice.

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9-to-25 pin serial RS232 cable

Firewire 800 and 400, mainly on Apple computers in the early aughts


Analog S-Video

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