VGA

“Pinout” is a term describing how an electrical cable is wired. Some cables do not have pinouts because they only contain a single internal wire, like coax cables. But if a cable has multiple pins on the end of the cable, it will have a pinout.

Each type of multi-pin cable has a standard pinout or two, but these layouts are not set in stone. Some machines will require non-standard pinouts; this will require users to use a custom cable.

Pinouts also come into play when using a cable with two different ends. For example, going from DB9 (9 pins) to DB25 (25 pins) will mean the DB25 side has 16 unused, “dead” pins.

If you need to know what pinout a cable needs, ideally there will be a spec sheet handy showing it. The next best option is contacting the manufacturer of the equipment the cable will be used with to see if they have a spec sheet available. If you have a cable tester available, that can be used to see how the pins line up. As a last resort, a cable can also be cut open to verify the pinout.

In the guide below, we will be highlighting the standard pinout configuration for common types of multi-pin cables.

Ethernet Pinouts

Ethernet uses two main pinouts, straight and crossover. Straight cables are used to connect computers to other devices, like modems and routers. Crossover cables are used to connect two computers directly. The wires inside ethernet cables are color-coded to industry standards, making it easy to follow the standard pinout options.

Straight pinouts are divided into two different options, T-568A and T-568B. The “B” option is the standard today, although finding the “A” cables still in use in older buildings

Cable switches are used to connect multiple signal inputs (computers, DVD players, video game consoles, etc.) to a single output (televisions, computer monitors, etc.). Switches all work on the same general principle and most are purely mechanical. A switch only goes from multiple inputs to one output; if you need to go from one input to multiple outputs, you will need a splitter instead.

Switches are used when you have a screen, such as a TV or computer monitor, that does not have enough ports. For example, say you have a TV with one HDMI port but you want to connect a DVD player, a laptop, and a video game console. One option would be to constantly reach behind the TV and switch the cables, but that gets old fast. The simpler solution would be using a switch that connects all three devices to the TV and lets you change between them at the push of a button.

Most switches are mechanical and do not require a power cable to work. The inside of a switch works similar to switching the rails on train tracks. Say you have a 2-way switch, so the signal can come in from Input A or Input B. If the switch is set to Input A and you press the button to change it to Input B, parts inside the switch move from A to B to change the connection. This is why switches can only use one input at a time. If a switch was built to use multiple signals at once, the signals would interfere with each other and none of them would work.

Coax

Audio and video cables go hand-in-hand, often being paired together. Some cables can even transmit audio and video on just one line. Over time a lot of new audio and video cables have been introduced, so the cable you need will often depend on the age of the equipment you are using. Most TVs, computers, and other devices can use multiple types of audio and video connections, so it is good to be able to identify them and know your options.

Audio-only cables include:

• 3.5mm
• 2.5mm
• ¼”
• Optical Toslink
• XLR
• SpeakOn
• MIDI

Video-only cables include:

• S-Video
• DB9
• VGA cables
• DVI

Audio/video cables include:

• F-type
• BNC
• RCA cables
• Component
• HDMI
• DisplayPort

Audio-only

3.5mm

3.5mm, also called ⅛” cables, is one of the most common audio cables. They are sometimes called “headphone jacks”, being the type of connection used for headphones. These ports are frequently found on cell phones, computers, and televisions.

There are a few different versions of 3.5mm: TS, TRS, and TRRS. TS cables will have one ring, dividing the metal sections into two conductors and are most often used for mono connections like microphones. TRS has two rings to give it three conductors, allowing them to be used for stereo connections such as speakers. TR