PC & Laptop Ports Explained: What Are All Those Connections?


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Jan 18, 2024

PC & Laptop Ports Explained: What Are All Those Connections?

Got a new PC or laptop and wondering what all ports and connections are for?

Got a new PC or laptop and wondering what all ports and connections are for? Here are some of the most common modern connection types, plus some of the older and deprecated connectors you might find on older hardware.

Though these connectors are designed primarily with data transfer in mind, they may also carry audio, power, or a network signal too.

The new ubiquitous connector, USB-C is a fully reversible 24-pin digital data connector. It can be used as a USB data port (including USB 3.1 and above), as a video connection (using DisplayPort Alternate Mode or HDMI Alternate Mode), as part of the Thunderbolt 3 or 4 specification, or as a means of charging peripherals using USB Power Delivery.

Not all USB-C cables are built alike, so make sure you pick a good one. As we race towards a future where USB-C dominates, you can upgrade your older cables with cheap adapters.

Modern Thunderbolt 3 and 4 ports share the USB-C connector, but they’re not necessarily the same. Many computers feature a small lightning bolt symbol next to Thunderbolt ports, and some laptops (like the 14 and 16-inch MacBook Pro) designate all USB-C ports as Thunderbolt connectors. Thunderbolt is an active technology, which means it has electrical circuitry in its connectors that are capable of high transfer speeds (up to 80Gb/sec on Thunderbolt 4).

Older Thunderbolt 1 and 2 connectors were different, featuring a non-reversible connector. You can buy adapters for these devices for use with modern Thunderbolt ports, though the speed remains capped at the oldest specification. Thunderbolt has some neat tricks that USB specifications lack, like the ability to daisy-chain connections.

Deprecated but still present on many new devices, USB-A is what many of us simply referred to as "USB" for most of our lives. It's a non-reversible connector that was first introduced in 1996 to replace slower and more cumbersome connectors like serial and parallel ports. Over the course of USB's lifespan transfer rates have gone from 1.5Mb/sec to 80 Gb/sec in USB 4 version 2.0.

USB-A connectors were deprecated after USB 3.1 in 2013, which means the maximum speed they’re capable of is 10Gb/sec. Many modern devices still include a USB-A port for compatibility, but you’re better off buying and using USB-C where possible.

An Ethernet port connects your computer to a wired network connection. Standardized in 1983, Ethernet began life with paltry speeds of just under 3Mb/sec with the latest standards capable of 400Gb/sec (with speeds of 1.6Tb/sec expected by 2025). To take advantage of higher speeds you’ll need the network interface (on your computer), router, and cabling to all be compatible with your desired speed.

The following is a selection of common power connectors that you can find on desktop and notebook computers. Be aware that USB-C (listed above) has become a common power connector for many laptops and peripherals.

Found on the back of most desktop computers and many game consoles, this connector is informally known as a "kettle plug" for its use in other consumer electronics. They’re also commonly used for amplifiers, audio and video equipment, monitors, and other peripherals.

Like the kettle plug, the "clover-leaf" is another common power adapter but one that's more commonly found on external laptop power adapters. The C6 male connector connects to a C5 socket on the power brick itself, with a plug on the other end to connect to mains power. There is then a thinner adapter cable that connects to the laptop.

Available in a vast range of sizes, a DC (direct current) barrel connector or jack is used to connect an external laptop power adapter to the laptop in question. These are less common than they once were since the arrival of USB Power Delivery, but many laptops still use them.

An Apple-specific power connector, MagSafe made its return with the 2021 14- and 16-inch MacBook Pro revision, with the 2022 MacBook Air redesign also including support for the format. The connector uses a magnet to hold it securely in place, with the magnet connection easily breaking away if the cord becomes snagged (preventing your laptop from being dragged off the desk).

MagSafe also appeared on older Apple computers but disappeared for around five years starting in 2016. MacBook models with MagSafe were introduced in 2021 and later use MagSafe 3, which is a different shape to MagSafe 2 which launched in 2012 (which itself is incompatible with the original MagSafe that debuted in 2006).

Want to carry video from your computer to a monitor, television, or projector? You’ll probably be using one of the following.

Commonly found on computer monitors (but not televisions), graphics cards, and laptops, the DisplayPort (DP) connector is a non-reversible 20-pin digital video connection. The standard was first released in 2006 as a means to replace DVI, VGA, and other outdated connectors. Like USB, the standard has evolved over the years to support higher bandwidth connections that allow for greater resolutions and faster refresh rates.

DP 1.4 (introduced in 2016) is arguably the most common iteration, supporting up to 32.4Gb/sec plus optional DSC (Display Stream Compression). DP 2.0 launched in late 2022, with a bandwidth of up to 80Gb/sec. In addition to video, the standard can also transport audio and USB data.

Short for High-Definition Multimedia Interface, HDMI is the most ubiquitous digital video connector in the world. Utilizing a 19-pin connector, HDMI was first introduced in 2002 and has gone through several iterations, introducing higher bandwidth capacities for greater resolutions, frame rates, and additional features like 3D and HDR video.

The HDMI 2.1 standard caps out at 48Gb/sec, capable of up to 10K video at 100Hz with DSC (Display Stream Compression). The standard is necessary to take advantage of 4K HDR video at 120Hz on consoles like the PlayStation 5, Xbox Series X, and graphics cards like the NVIDIA 30 and 40 series. It also includes built-in support for variable refresh rate (VRR) using HDMI AdaptiveSync.

HDMI transfers video, audio, ethernet, and CEC (Consumer Electronics Control) data for controlling other connected devices. Technologies like ARC (Audio Return Channel) are built on the HDMI standard.

Still found on some laptops, Mini HDMI is a smaller version of standard HDMI. It has the same 19-pin connector, but it's a lot smaller to save space. To use the Mini HDMI port with a TV or monitor that features a full-sized HDMI port you need a cable with one of each connector on either end (or an adapter).

Don't confuse Mini HDMI with Micro HDMI, which was more common on smartphones and action cameras.

Outdated, but still found on some recent devices from the last five years or so (particularly TVs), VGA stands for Video Graphics Array and it's a 15-pin analog video connector that was especially common on chunky old CRT monitors, projectors, and early flat-screen LCDs. Though old, VGA managed to stick around long past its due as a "PC port" on many smart TVs.

Audio is now often bundled with video connections like HDMI and DisplayPort, but dedicated audio connections are still present on most computers for both input and output.

Commonly used for two-channel stereo audio and microphone input, 3.5mm jacks are common on all types of computers. You’ll find them on the back of a desktop often with separate output and input ports, on the front of PC cases, and on laptops with mixed-use ports. Typically speaking, green ports are used for stereo output while red ports signify a microphone input.

These outputs use integrated digital-to-analog converters (DACs) which make it easy to connect your computer to external speakers or an old amplifier.

Optical cables carry a digital audio signal using a special fiber optic cable. TOSLINK is short for "Toshiba Link" and is named after the company that created the standard. S/PDIF stands for "Sony/Philips Digital Interface" and it refers to the software component of the standard.

Though they deliver a "cleaner" sound than analog connections and are not subject to interference from radio frequencies or ground loops, optical does have some drawbacks. Plastic optical cables are usually limited to 5 or 10 meters in length due to the potential for signal degradation, and cables can become damaged from being bent or compressed.

The following ports may be found on older hardware but are rarely included on modern devices.

Not really a port at all, a Kensington Lock slot allows you to attach a keyed or combination lock to your laptop to prevent it from being stolen. They’re designed to secure your laptop to a desk or any solid nearby object, ideal if you need to step away from your laptop and you aren't confident about leaving it behind.

Though many laptops still include Kensington Lock slots, they’re arguably less common than they once were.

Used to connect keyboards and mice, the PS/2 connector is a 6-pin mini-DIN connector that was eventually replaced by USB Type-A. Computer motherboards and laptops would often have two PS/2 connectors, a purple one for keyboards and a green one for mice. The connector was also found on older home computers and consoles, including the Sega Genesis and IBM Personal System/2 after which it got its name.

Developed by Apple, Sony, and Panasonic, IEEE 1394 was more commonly known as FireWire (but also went by i.LINK on Sony devices and Lynx on Texas Instruments devices). The standard was used for high-speed data transfers and power delivery, so it's no surprise that its main competitor was USB.

IEEE 1394 had much faster transfer rates than USB at the time, with up to 400Mb/sec possible in the original 1995 specification. FireWire 800 came in 2002, doubling the maximum theoretical transfer rate. FireWire was used in cameras (especially DV cameras), audio recorders, network devices, and even early iPod models shipped with a FireWire cable instead of a USB one.

Short for Digital Video Interface, DVI was designed as a replacement for VGA to carry a video signal from a computer to a display (commonly a computer monitor). DVI covered both analog and digital signal transmission, depending on the type of connector used. This included DVI-I for both digital and analog (backward compatibility with VGA) or DVI-D (digital-only) and DVI-A (analog-only).

On top of this, DVI could be dual or single link. Dual link would double the available bandwidth from 4.95Gb/sec to 9.9Gb/sec. The standard was replaced by DisplayPort and (to a lesser extent) HDMI in the mid-2000s.

Commonly found on computers from the 1970s onwards, parallel ports were relatively large 25-pin connectors with screw-in fasteners designed for connecting peripherals like printers, network devices, hard drives, tape drives, video capture devices, and more. The parallel port wasn't fully standardized until 1994 (as IEEE 1284), with a maximum bandwidth of 2.5MB/sec (20Mb/sec) with the use of the Extended Capability Port.

The port got its name from the method of data transfer, where bits of data could be transferred simultaneously in parallel. Parallel was eventually superseded by USB (particularly USB 2.0) and integrated network interfaces.

Designed as an expansion port for laptops and standardized by the Personal Computer Memory Card International Association in 1990, PC Card was effectively a smaller version of the parallel port but for portable computers. It was designed to add functionality to laptops of the time such as fax, dial-up, Ethernet, storage, and eventually even wireless networking.

The cards were even used in a handful of digital SLR cameras and in-car navigation systems.

A serial port is a now (mostly) defunct method of communicating with other computers, network peripherals like modems, printers, mice, external drives, point-of-sales terminals, and bespoke electronics. Defined under the 1969 RS-232 standard, serial ports came in both 25-pin and 9-pin variants.

Like parallel, serial gets its name from the method of data transfer where data is sent and received sequentially rather than simultaneously.

These ports are all designed with cables in mind, but there's more to cables than first meets the eye. For example, do you know how to pick the right Ethernet cable? Or that not all USB-C cables are Thunderbolt compatible? Or how to avoid being ripped off when buying an HDMI cable?

Check out out round-ups of the best USB-C cables, the best Ethernet cables, and the best HDMI cables.



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