USB A vs USB C: The Past, Present and Future of the USB Standard
Universal Serial Bus, better known as USB, has become the standard interface used to connect everything from computers and phones to cameras, game controllers, printers, storage devices and more to each other and to power sources. This article will examine the evolution of USB technology from the original USB A to the latest USB C incarnation. We’ll explore the differences in design, performance, capabilities and real-world usage between the two to understand USB A vs USB C.
A Brief History of USB
USB was created in the mid 1990s to standardize the connection of computer peripherals. Before USB, connecting devices often required plugging into specific ports, installing expansion cards, configuring IRQ channels and other complexities. The computer industry knew consumers needed something simpler.
The USB Implementers Forum was founded by Compaq, DEC, IBM, Intel, Microsoft, NEC and Nortel in 1995. After several revisions, they released the initial USB 1.0 specification in January 1996. It specified data rates up to 12 Mbps, along with specifications for cables, connectors and device classes.
The iconic rectangular USB A plug and port shape we still recognize today was part of that original 1.0 USB release. It featured four pins to deliver power and data. While USB could connect up to 127 peripherals through daisy chaining hubs and devices, the cable was not designed to deliver power on its own. Many early devices like keyboards, mice, and game controllers didn’t need much power though.
Over the next two decades, the USB standard saw several major updates to improve performance and capabilities:
- USB 1.1 (1998): Fixed bugs in early implementations
- USB 2.0 (2000): Introduced higher maximum signaling rate of 480 Mbps
- USB 3.0 (2008): SuperSpeed mode increased signaling rate to 5 Gbps
- USB 3.1 (2013): SuperSpeed+ mode delivered 10 Gbps data rate
While connector shapes and cable colors differed slightly across some versions, the basic USB A rectangular shape we are all familiar with persisted over decades. Behind the scenes though, outdated versions with slower maximum data rates lingered. Consumers had to pay attention to whether their device, cable or port was USB 1.0, 2.0 or 3.x rated to understand expected performance.
Enter USB Type C
After nearly 20 years of rectangular USB A ports and plugs, the USB standard received its first major physical redesign in 2014 with USB Type C. Where USB developments used to focus on optimizing data transmission speed, this USB C incarnation delivered an entirely new compact connector shape.
Rather than relying on a rectangular shape that only plugged in one orientation, USB C utilizes a uniform connector design that plugs in either vertically or inverted. This reversible form factor finally addressed the minor frustration we’ve all felt when trying to plug in USB only to flip the connector one or more times!
But easy plugging was not the only benefit. The USB Type C connector shape is considerably smaller than USB A and packs 24 pins compared to USB A’s four. This expands possibilities for faster data bandwidth, increased power delivery for connected devices, and even alternate modes beyond data and power like video.
USB Type C expanded what USB could do:
- Faster data speeds: Up to 40 Gbps under the USB 3.2 specification
- Power delivery: Up to 100 watts, enough to charge laptops and other large devices
- Single cable docking: Alternate modes for video, audio and networking allow USB C ports to replace multiple ports
- Small and durable: The smaller connector is more convenient across increasingly portable devices
USB A vs USB C: Key Specifications Compared
Now that we’ve covered the history of USB A and how USB C aims to improve upon it, let’s compare some key specifications to understand just what makes USB C better.
Data Transfer Speeds
USB A originally supported up to 12 Mbps throughput for low bandwidth devices like keyboards and mice. Updated versions boosted this over the years, reaching a maximum data rate of 10 Gbps on USB 3.1.
USB C jumps even further – with USB 3.2 supporting up to 20 Gbps and Thunderbolt 3 enabled implementations delivering an extremely fast 40 Gbps speed.
This makes USB C the easy choice for high resolution cameras, external storage solutions like SSDs and flash drives, external graphics cards, and any other peripherals that need to transfer large amounts of data quickly.
Power Delivery
The USB Power Delivery specification increases power delivery from a maximum of just 2.5 watts on early USB A implementations up to 100 watts on USB C.
This means properly equipped USB C cables and ports can charge far more power-hungry devices. USB C can charge larger phones, tablets, and even full size laptops that USB A cables simply can’t juice up.
Alternate Modes
Unlike USB A connectors limited to just power and data, USB C introduces support for alternate modes. This allows USB C ports and cables to carry protocols like DisplayPort video alongside USB data.
With the right adapters, docking stations and cables, USB C can deliver video to multiple monitors at resolutions exceeding 4K from a single port. Networking, analog audio, device control signals and other alternate modes are also possible.
This key specification opens up an entire world of single cable docking solutions to simplify connections across corporate and home offices.
Design
As explored earlier, the USB C connector itself sports an entirely new design from USB A:
- Reversible/symmetrical connector that plugs in either way like Apple’s Lightning
- Elliptical port shape instead of USB A rectangle
- Just 8.4mm by 2.6mm connector size, under half the length of USB A
- Durability – Rated for 10,000 cycles minimum
This refreshed industrial design factors heavily into USB C’s utility for modern slim devices versus dated USB A ports. The smaller connector takes up less space within ever-shrinking mobile devices, allowing more room for batteries. The reversible approach also just makes it much easier to plug in quickly.
USB A vs USB C In Practice
By now the technological advantages of USB C over dated USB A implementations are clear. But what about practical application? The world won’t change over to the new standard overnight.
In practice you are likely to own devices utilizing both USB standards for years to come. Understanding when to rely on each, and how to bridge between USB C and USB A devices remains important.
USB C as Future Standard
Any newly manufactured device, whether phone, tablet, camera, external drive or more should come equipped solely with USB C ports. Creative professionals focused on moving data quickly will insist on USB C or Thunderbolt 3 equipped devices.
But USB A remains in use across older peripherals. The USB Implementers Forum estimates 8 billion USB A devices exist! These rely on those familiar rectangular USB A ports and cables even if their specs limit speeds below 480 Mbps.
Use Adapters As Needed
With billions of USB A devices but a switch to USB C across most newer gear, adapters bridge the gap during this transition.
Simple USB C to USB A adapters or cables connect devices with the latest connectors to older equipment still sporting USB A ports. More advanced hubs and docking stations can actually equip older USB A computers with the latest high speed USB C and Thunderbolt 3 ports.
Invest in quality adapters, hubs and cables as needed to integrate the latest fast USB C gear with USB A legacy devices.
My Experience: USB A to USB C
Having used computers for decades, I still have storage devices, scanners, controllers, keyboards and mice locked into USB A connections. But I built a new Thunderbolt 3 equipped workstation last year to transfer large batches of photos quickly.
The freedom of docking this compact system to dual 4K displays, external SSD storage, cameras, networks and more in a streamlined fashion via USB C ports proved eye-opening after so many years of rectangular USB A plugs.
My old USB A devices still plug away for now via some USB C adapters. But the sheer speed, convenience and versatility of even just data transfers using the USB C and Thunderbolt interfaces makes it hard to go back to limiting older USB A approaches. I’m converted to the promise USB C offers as the new standard!
USB C: The Obvious Future USB Standard
The decision between USB A vs USB C from a pure performance and capability standpoint seems quite obvious in favor of USB C. With faster potential data rates measured in gigabytes per second instead of megabytes, far more power delivery and advanced alternate mode potential unlocking convenience via single cable docking – USB Type C outshines dated USB A across the board.
Its streamlined, smaller and reversible connector also perfectly pairs with modern priorities like portability and quick charging. Just as USB itself replaced a confusing maze of serial, parallel, PS/2, FireWire and other ports to simplify PC connectivity in the 90s, USB C now outperforms the first USB standard introduced way back in 1996.
Of course the huge USB A installed base measuring in the billions of devices doesn’t go away overnight. You’ll be using USB A ports, peripherals and cables for years via adapters as this latest USB standard slowly penetrates the masses. But make no mistake – USB C is the future, and the obvious winner of USB A vs USB C.
