This post is about cables — and their corresponding ports — used to connect computer devices (for example, a laptop or a smartphone) to each other and to computer peripheral devices (for example, a monitor or a keyboard).
In this post:
Required knowledge:
Terminology
Keyed
“Keyed” means the plug must be inserted the “right way up”. The plug and port must physically match up for the plug to fit into the port.
Hot-swappable
The term “hot-swappable” means that switching the computer off before removing or inserting the connector in or out of the port is unnecessary.
EMI
You will often see solid barrel-shaped objects around a cable near each end. This ferrite bead (also known as a ferrite block, ferrite core, ferrite ring, EMI filter, or ferrite choke) is a type of choke that suppresses high-frequency electronic noise in electronic circuits. [1]
Bus
A “bus” is a connection to the motherboard.
PS/2
Personal System 2 (“PS/2”) ports existed on computers to connect mice and keyboards. The technology has been replaced by USB and wireless options (e.g. Bluetooth).
COM
Communication (“COM”) ports are the serial and parallel ports found on older computers and printers.
You will still see them and may even use them, even if only virtually. For example, the microcontroller I have connected to one of my laptop’s USB ports is listed as being on COM5 (COM port 5), which is an emulated port created by a USB adapter. My laptop has no physical serial or parallel ports.
- Open the Device Manager
- Expand the Ports (COM & LPT) option
- The ports are listed
VGA
Video Graphics Array (“VGA”) is capable of transferring video data only.
15 pins arranged in 3 rows in a male plug that is usually blue with a port with a corresponding female port that is usually a matching blue.
The VGA port is part of an expansion card but is most often integrated with the motherboard.
VGA is being replaced with HDMI.
AVI
Audio Video Interface (“AVI”)
HDMI
A High-definition Multimedia Interface (“HDMI”) cable is hot-swappable and keyed. It can transfer audio and video signals. Most new laptops and PCs now come with an HDMI port as well as the older VGA port.
Lightning connector
An easy description of a Lightning connector would be that this is Apple’s answer to USB. It is hot-swappable and, unlike most USBs, can be inserted any way up (USB-C can be connected either way up).
As of 2023, Apple is dropping its proprietary Lightning connector and implementing USB-C.
USB
Universal Serial Bus (“USB”) is hot-swappable. Only the latest version, USB Type-C, is not keyed. It has replaced older technologies such as serial ports.
USB-B
Typically used to connect printers and scanners.
USB-C
As USB-C is phased in, we are seeing many cables with USB-C on the device end and standard USB on the computer side. This is because older computers do not have USB-C ports. Newer computers will have USB-C ports onboard.
Out with the old…
…in with the new!
Randoms
In all my years of working in IT I cannot remember owning a device with either of the following types of connectors.
References:
- Wikipedia contributors. (No date) Ferrite bead. Available at: https://en.wikipedia.org/w/index.php?title=Ferrite_bead&oldid=1166263188 (accessed October 24, 2023).
- Wikipedia contributors. (No date) DisplayPort. Available at: https://en.wikipedia.org/w/index.php?title=DisplayPort&oldid=1181233409 (accessed October 24, 2023).
- Wikipedia contributors. (No date) Digital Visual Interface. Available at: https://en.wikipedia.org/w/index.php?title=Digital_Visual_Interface&oldid=1180113591 (accessed October 24, 2023).