USB-C Introduction: What You Really Need to Know About the Connector Taking Over the World

USB-C is the latest iteration of the USB interface’s connector developed by the USB Implementers Forum with the goal of creating a connector that could become the definitive connector for all consumer electronic users, so that any and all devices could utilize the same connector to transmit data and/or power. Physically speaking, it features 24-pins within an oval-like design that is about half the size of the commonly used USB-A connector, or roughly equivalent to the size of a Micro-USB connector.

Because of the overarching goal of making USB-C as universal as possible (some writers describe the goal as being the creation of “one connector to rule them all”), the engineering behind the USB-C connector was meant to support a wide variety of specifications beyond the standard USB transmission specifications, almost as if the connector was meant to act as a blank canvas for various data and power transmission interfaces to apply their technology. As such, its design gives the USB-C connector the following four distinct capabilities:

NOTE: USB-C is a designation of the connector’s physical interface (its design and form factor) and should not be confused with USB versions, such as “USB 3.2”, which govern data and power transfer specifications.

• 
  Connector reversibility

Whereas USB-A connectors have to be plugged into their ports in a specific orientation, the symmetry of the oval shaped USB-C connector head, along with the pin configuration within it, allows the USB-C connector to be completely reversible so that it can be plugged in any orientation, thereby adding a greater level of convenience to the already widely enjoyed functionality of the USB interface.

• 
  Alt-Mode for combining multiple interfaces

As described above, USB-C from its onset was specifically designed as a vehicle not only for the standard USB transmission specifications, but also for an array of non-USB transmission technologies and specifications. As a result of this objective, the USB-C connector features an Alt-Mode capability which allows it to support various transmission interfaces such as the DisplayPort display interface and/or the Thunderbolt interface. In other words, for some devices, DisplayPort and Thunderbolt data/video signals are able to be transmitted via the device’s USB-C ports depending on the device’s level of support (more on this later).

• Two-way power charging via Power Delivery 3.0 technology

Another feature of USB-C that further bolsters its overall flexibility, is its Power Delivery 3.0 technology which not only provides up to 100W of charging, but also allows for two-way charging. With two-way charging, a USB-C port has the potential to either output power in order to charge a connected device, or input power from a connected device in order to charge itself. So for users of products such as laptops, you’ll not only be able to charge your laptop via the same USB-C port that you use to transfer files, but you’ll also be able to let your laptop charge your smartphone using that same USB-C port.

• 
  Digital audio conversion into analog sound

As most users of the newer generations of smartphones know, brands are increasingly eliminating the headphone jacks in order to accommodate the device’s hardware. Their ability to do so, and replace it with a USB-C port, is mainly a result of USB-C’s ability to convert digital audio into analog sound, which allows for users to still be able to use their 3.5mm headphone plug (by way of a simple adapter) with their smartphone.

Despite all the capabilities described above, it is important to note that not all USB-C products support USB-C’s full functions. Of the four features listed, only connector reversibility is a feature inherent in all USB-C connectors/ports. For the remaining three capabilities, their level of support depends on the cost-related hardware decisions made by the manufacturers of the products utilizing them. This is in keeping with the by-design flexibility of USB-C which allows manufacturers the ability to pick-and-choose the level of USB-C functionality available in their product designs. So for some brands who might want to target a low-to-mid price point, the USB-C port on their product might only support the data speeds of the newest version of the USB specifications (USB 3.2 Gen2), while a brand more focused on the high-end market might have products with USB-C ports that support Power Delivery 3.0 and Thunderbolt Alt-Mode.

One of the main draws for USB-C touched on before, as well as one of the main sources of confusion, is its Alt Mode capability. As described above, Alt Mode allows USB-C ports to transfer data/video via multiple interfaces, including the increasingly popular DisplayPort video interface. USB-C ports which are able to transfer DisplayPort signals are either called USB-C DisplayPort or DP Alt Mode. They allow you to connect video sources (e.g. PCs, Blu-Ray players, etc.) and display devices (e.g. TVs, projectors, etc.) that support DisplayPort to each other via their USB-C ports to broadcast high-definition video.

The confusion over USB-C DisplayPort arises from fact that not all USB-C ports feature DisplayPort Alt Mode functionality (as explained in the previous section) coupled with the lack of clarity many brands provide over the level of support their USB-C products have with regards to DisplayPort functionality. As a consequence, a lot of users with devices that feature USB-C ports are entirely unaware of whether or not those ports support DisplayPort over USB-C. The key for these users is to understand how to identify whether their USB-C device supports DisplayPort over USB-C.

Given the confusion over USB-C DisplayPort, the next logical question is to ask how a user is able to know whether their device supports DisplayPort over USB-C. As there is currently no standard way for identifying a USB-C DisplayPort directly on the device – some brands don’t even bother printing the DisplayPort logo on the ports that support it for their products – the best method to decipher whether your device supports DisplayPort over USB-C is to check either the product specs on the manufacturer’s official website or to check websites with in-depth product reviews and/or information. Within those sites you’ll be able to find detailed breakdowns of each ports on the device.

*Not all laptops and mobile phones with USB-C ports that support USB-C full functions.

**Laptops and mobile phones have different combinations of USB-C functions.

Similar to the confusion around USB-C DisplayPort Alt Mode, there is also an equal amount of confusion around whether USB-C and the Thunderbolt transfer interface made popular by Apple products are compatible. The simple answer is that its Alt-Mode functionality also allows USB-C to support the latest version of the Thunderbolt interface, Thunderbolt 3. But just as how not all USB-C ports feature DisplayPort Alt Mode functionality, not all USB-C ports feature Thunderbolt 3 functionality. Thunderbolt 3 functionality must be explicitly designed into a device’s USB-C port by its manufacturer in order for the USB-C port to be able to support Thunderbolt 3 connections.

For Mac users the newer generation of Macs, including the iMac Pro, iMac 2017, Mac Mini 2018, MacBook Air 2018, and all MacBook Pros released from 2016 on, do support USB-C Thunderbolt 3 ports, but again it is worth double-checking official product specs (especially for non-Mac users) to confirm the level of support for their device’s USB-C ports.

NOTE: Thunderbolt 3 ports require the use of Thunderbolt 3 cables in order for their transmissions to work. 

One last item of note for users of devices with Thunderbolt 3 ports is that Thunderbolt 3 itself also supports DisplayPort functionality, meaning Thunderbolt 3 ports will also be able to transmit video to DisplayPort devices.