# USB-C

USB-C, or USB Type-C, is a 24-pin, reversible connector (not a protocol) that supersedes previous USB connectors and can carry audio, video, and other data, to connect to monitors, external drives, hubs/docking stations, mobile phones, and many more peripheral devices. It can also provide and receive electricity to power, for example, a laptop or a mobile phone. It is used not only by USB technology, but also by other protocols, including Thunderbolt, PCIe, HDMI, DisplayPort, and others. It is extensible to support future protocols.
The design for the USB-C connector was initially developed in 2012 by Intel, HP Inc., Microsoft, and the USB Implementers Forum. The Type-C Specification 1.0 was published by the USB Implementers Forum (USB-IF) on August 11, 2014. In July 2016, it was adopted by the IEC as "IEC 62680-1-3".
The USB Type-C connector has 24 pins and is reversible. The designation C distinguishes it from the various USB connectors it replaced, all termed either Type‑A or Type‑B. Whereas earlier USB cables had a host end A and a peripheral device end B, a USB-C cable connects either way; and for interoperation with older equipment, there are cables with a Type-C plug at one end and either a Type-A (host) or a Type-B (peripheral device) plug at the other. The designation C refers only to the connector's physical configuration, or form factor, not to be confused with the connector's specific capabilities and performance, such as Thunderbolt 3, DisplayPort 2.0, USB 3.2 Gen 2×2. While USB‑C is the single modern connector for all USB protocols, there are valid uses of the connector that do not involve any USB protocol. Based on the protocols supported by all, host, intermediate devices (hubs), and peripheral devices, a USB-C connection normally provides much higher signalling and data rates than anything using the superseded connectors.
A device with a Type-C connector does not necessarily implement any USB transfer protocol, USB Power Delivery, or any of the Alternate Modes: the Type-C connector is common to several technologies while mandating only a few of them.
USB 3.2, released in September 2017, fully replaced the USB 3.1 and USB 3.0 specifications. It preserves the former USB 3.1 SuperSpeed and SuperSpeed+ data transfer modes and introduces two additional data transfer modes by newly applying two-lane operations, with signalling rates of 10 Gbit/s (SuperSpeed USB 10 Gbps; raw data rate: 1.212 GB/s) and 20 Gbit/s (SuperSpeed USB 20 Gbps; raw data rate: 2.422 GB/s). They are only applicable with Full-Featured USB-C Fabrics (connectors, cables, hubs, host, and peripheral device) at all connections.
USB4, released in 2019, is the first USB transfer protocol standard that is applicable exclusively via USB-C.

## Ease of use

The USB-C standard simplifies usage by specifying cables having identical plugs on both ends, which can be inserted without concern about orientation. When connecting two devices, the user can plug either end of the cable into either device. The plugs are flat, but will work if inserted right-side-up or upside-down.
The USB-C plugs have two-fold rotational symmetry because a plug may be inserted into a receptacle in either of two orientations. Electrically, USB-C plugs are not symmetric, as can be seen in the tables of pin layouts. Also, the two ends of the USB-C are electrically different, as can be seen in the table of cable wiring. The illusion of symmetry results from how devices respond to the cable. Software makes the plugs and cables behave as though they are symmetric. According to the specifications, "Determination of this host-to-device relationship is accomplished through a Configuration Channel (CC) that is connected through the cable."
The USB-C standard attempts to eliminate the need to have different cables for other communication technologies, such as Thunderbolt, PCIe, HDMI, DisplayPort and more. Over the past decade, many companies have adopted the USB-C standard into their products. USB-C cables can contain circuit boards and processors giving them much more capability than simple circuit connections.

## Overview

USB-C cables interconnect hosts and peripheral devices, replacing various other electrical cables and connectors, including all earlier (legacy) USB connectors, HDMI connectors, DisplayPort ports, and 3.5 mm audio jacks.

### Name

USB Type-C and USB-C are trademarks of the USB Implementers Forum.

### Connectors

The 24-pin double-sided connector is slightly larger than the non-SuperSpeed, USB 2.0 Micro connectors, with a USB-C receptacle opening measuring 8.34 mm × 2.56 mm, 6.20 mm deep.

### Cables

Type-C cables can be split among various categories and subcategories. The first one is USB 2.0 or Full-Featured. Like the names imply, USB 2.0 Type-C cables have very limited wires and are only good for USB 2.0 communications and power delivery. They are also called charging cables colloquially. Conversely, Full-Featured cables need to have all wires populated and in general support Alt modes and are further distinguished by their speed rating.
Full-Featured cables exist in four different speed grades. Their technical names use the "Gen A" notation, each higher number increasing capabilities in terms of bandwidth. The user-facing names are based on the bandwidth a user can typically expect "USB 5Gbps", "USB 20Gbps", "USB 40Gbps" and so on. This bandwidth notation considers the various USB standards and how they use the cable. A Gen 1 / 5 Gbit/s cable supports that bandwidth on every one of its 4 wire pairs. So technically it could be used to establish a USB3 Gen 1x2 connection with nominally 10 Gbit/s between two "SuperSpeed USB 20 Gbps" capable hosts. For a similar reason, the "USB 10Gbps" name is deprecated, as that is using only 2 of the 4 wire-pairs of a Gen 2 cable and thus synonymous with "USB 20Gbps" cables. The signal quality that the "Gen A" notation guarantees or requires is not uniform across all USB standards. See table for details.
The USB Implementers Forum certifies valid cables so they can be marked accordingly with the official logos and users can distinguish them from non-compliant products. There have been simplifications in the logos. Previous logos and names also referenced specific USB protocols like SuperSpeed for the USB3 family of connections or USB4 directly. The current official names and logos have removed those references as most full-featured cables can be used for USB4 connections as well as USB3 connections.
In order to achieve longer cable lengths, cable variants with active electronics to amplify the signals also exist. The Type-C standard mostly mandates these active cables to behave similar to passive cables with vast backwards compatibility. But they are not mandated to support all possible features and typically have no forward compatibility to future standards. Optical cables are even allowed to further reduce the backwards compatibility. For example, an active cable may not be able to use all high speed wire-pairs in the same direction (as used for DisplayPort connections), but only in the symmetric combinations expected by classic USB connections. Passive cables have no such limitations.

#### Power delivery

Every normal USB-C cable must support at least 3 amps of current and up to 20 volts for up to 60 watts of power according to the USB PD specification. Cables are also allowed to support up to 5 A (with 20 V limit up to 100 W of power). However, the 20 V limit for 5 A cables has been deprecated in favor of 50 V. The combination of higher voltage support and 5 A current support is called EPR and allows for up to 240 W (48 V, 5 A) of power according to the USB PD specification.

#### E-Marker

All Type-C cables except the minimal combination of USB 2.0 and only 3 A must contain E-Marker chips that identify the cable and its capabilities via the USB PD protocol. This identification data includes information about product/vendor, cable connectors, USB signalling protocol (2.0, Gen speed rating , Gen 2), passive/active construction, use of V$_{CONN}$ power, available V$_{BUS}$ current, latency, RX/TX directionality, SOP controller mode, and hardware/firmware version. It also can include further vendor-defined messages (VDM) that detail support for Alt modes or vendor specific functionality outside of the USB standards.

#### Cable types

Overview of passive and active Type-C cables and their USB features :
| Cable type | Cable type | Speed | Marketing names | Exp. max. cable length | USB2 | USB3 | USB4 | TB3 | DP | Power Transfer |
| | Remarks | Speed | Marketing names | Exp. max. cable length | USB2 | USB3 | USB4 | TB3 | DP | Power Transfer |
| USB 2.0 | — | — | Hi-Speed USB | ≤ 4m | Yes | No | | No | No | USB PD: 60W or 100W or 240W |
| Full-Featured passive | — | Gen 1 | USB 5Gbps | ≤ 2m | Yes | 5 Gbit/s (or Gen 1x2) | 20 Gbit/s | No | Yes | USB PD: 60W or 100W or 240W |
| Full-Featured passive | — | Gen 2 | USB 20Gbps (USB 10Gbps deprecated) | ≤ 1m | Yes | Yes | 20 Gbit/s | 20 Gbit/s | Yes | USB PD: 60W or 100W or 240W |
| Full-Featured passive | (incl. passive TB4 & TB5) | Gen 3 & Gen 4 | USB 40Gbps USB 80Gbps | ≤ 0.8m | Yes | Yes | 80 Gbit/s (or asymm.) | Yes | Yes | USB PD: 60W or 100W or 240W |
| Full-Featured active (also optical hybrid) | — | Gen 2 | USB 20Gbps (USB 10Gbps deprecated) | < 5m | Yes | Yes | 20 Gbit/s | Yes | Optional | USB PD: 60W or 100W or 240W |
| Full-Featured active (also optical hybrid) | (incl. active TB4) | Gen 3 | USB 40Gbps | < 5m | Yes | Yes | 40 Gbit/s | Yes | Optional TB up to 2m | USB PD: 60W or 100W or 240W |
| Full-Featured active (also optical hybrid) | (incl. active TB5) | Gen 4 | USB 80Gbps | < 5m | Yes | Yes | 80 Gbit/s (or asymm.) | Yes | Optional TB up to 2m | USB PD: 60W or 100W or 240W |
| Full-Featured active (also optical hybrid) | USB3 active | Gen 2 | ? | < 5m | Yes | Yes | | No | Optional | USB PD: 60W or 100W or 240W |
| OIAC | USB3 | Gen 2 | ? | ≤ 50m | only if optical | Gen 2 only (10 / 20 Gbit/s) | | No | Optional | — |
| OIAC | USB4 | Gen 3 | ? | ≤ 50m | only if optical | Gen 2 only (10 / 20 Gbit/s) | 40 Gbit/s | Optional | Optional | — |
| OIAC | USB4 | Gen 4 | ? | ≤ 50m | only if optical | Gen 2 only (10 / 20 Gbit/s) | 80 Gbit/s (asymm. optional) | Optional | Optional | — |
* ↑ Maximum cable lengths are not normative, but simply estimates of the USB specification, based on the expected physical limits of conventional copper cables.
* ↑ USB4 Gen 2 has less strict signal requirements than USB 3 Gen 2. Spec compliant USB3 Gen 1 cables should support USB4 Gen 2 / 20 Gbit/s connections
* 1 2 No specific maximum Displayport speed guaranteed by Type-C specification
* 1 2 TB4 (Thunderbolt 4) & TB5 (Thunderbolt 5) cables up to 2m length (active & passive) are "universal cables", including DP (DisplayPort) support. DP guarantees may only include the highest speeds covered by DP 1.4 for TB4 (HBR3) or DP 2.1 for TB5 (UHBR20).
* 1 2 No specific maximum Displayport speed guaranteed by Type-C specification. Different types of active cable implementations may behave differently.
* ↑ As "optically isolated" implies, these cables cannot transfer power and are not allowed to have electrically conductive connections between both ends. Each cable end's active electronics must be powered by the local port. They thus cannot work with bus-powered devices.

### Hosts and peripheral devices

For any two pieces of equipment connecting over USB, one is a host (with a downstream-facing port, DFP) and the other is a peripheral device (with an upstream-facing port, UFP). Some products, such as mobile phones, can take either role, whichever is opposite that of the connected equipment. Such equipment is said to have Dual-Role-Data (DRD) capability, which was known as USB On-The-Go in the previous specification. With USB-C, when two such devices are connected, the roles are first randomly assigned, but a swap can be commanded from either end, although there are optional path and role detection methods that would allow equipment to select a preference for a specific role. Furthermore, Dual-Role equipment that implements USB Power Delivery may swap data and power roles independently using the Data Role Swap or Power Role Swap processes. This allows for charge-through hub or docking station applications such as a portable computer acting as a host to connect to peripherals but being powered by the dock, or a computer being powered by a display, through a single USB-C cable.
USB-C devices may optionally provide or consume bus power currents of 1.5 A and 3.0 A (at 5 V) in addition to baseline bus power provision; power sources can either advertise increased USB current through the configuration channel or implement the full USB Power Delivery specification using both the BMC-coded configuration line and the legacy BFSK-coded V$_{BUS}$ line.
All older USB connectors (all Type-A and Type-B) are designated legacy. Connecting legacy and modern, USB-C equipment requires either a legacy cable assembly (a cable with any Type-A or Type-B plug on one end and a Type-C plug on the other) or, in very specific cases, a legacy adapter assembly.
An older device can connect to a modern (USB-C) host by using a legacy cable, with a Standard-B, Mini-B, or Micro-B plug on the device end and a USB-C plug on the other. Similarly, a modern device can connect to a legacy host by using a legacy cable with a USB-C plug on the device end and a Standard-A plug on the host end. Legacy adapters with USB-C receptacles are "not defined or allowed" by the specification because they can create "many invalid and potentially unsafe" cable combinations (being any cable assembly with two A ends or two B ends). However, exactly three types of adapter with USB-C plugs are defined: 1. A Standard-A receptacle (for connecting a legacy device (such as a flash drive—not a cable) to a modern host, and supporting up to USB 3.1). 2. A Micro-B receptacle (for connecting a modern device to a legacy host, and supporting up to USB 2.0). 3. The Audio adapter accessory mode defined below, in the next section.

### Non-USB modes
#### Audio adapter accessory mode

A device with a USB-C port may support analog headsets through an audio adapter with a 3.5 mm jack, providing three analog audio channels (left and right output and microphone). The audio adapter may optionally include a USB-C charge-through port to allow 500 mA device charging. The engineering specification states that an analog headset shall not use a USB-C plug instead of a 3.5 mm plug. In other words, headsets with a USB-C plug should always support digital audio (and optionally the accessory mode).
Analog signals use the USB 2.0 differential pairs (Dp and Dn for Right and Left) and the two side-band use pairs for Mic and GND. The presence of the audio accessory is signaled through the configuration channel and V$_{CONN}$.

#### Alternate modes

An Alternate Mode dedicates some of the physical wires in a USB-C cable for direct device-to-host transmission using non-USB data protocols, such as DisplayPort or Thunderbolt. The four high-speed lanes, two side-band pins, and (for dock, detachable device and permanent-cable applications only) five additional pins can be used for Alternate Mode transmission. The modes are configured using vendor-defined messages (VDM) through the configuration channel.

## Specifications
### USB Type-C cable and connector specifications

The USB Type-C specification 1.0 was published by the USB Implementers Forum (USB-IF) and was finalized in August 2014.
It defines requirements for cables and connectors.
* Rev 1.1 was published 2015-04-03
* Rev 1.2 was published 2016-03-25
* Rev 1.3 was published 2017-07-14
* Rev 1.4 was published 2019-03-29
* Rev 2.0 was published 2019-08-29
* Rev 2.1 was published 2021-05-25 (USB PD Extended Power Range: 240 W as 48 V × 5 A)
* Rev 2.2 was published 2022-10-18, primarily for enabling USB4 Version 2.0 (80 Gbps) over USB Type-C connectors and cables.
* Rev 2.3 was published 2023-10-31.
Adoption as IEC specification:
* IEC 62680-1-3:2016 (2016-08-17, edition 1.0) "Universal serial bus interfaces for data and power – Part 1-3: Universal Serial Bus interfaces – Common components – USB Type-C cable and connector specification"
* IEC 62680-1-3:2017 (2017-09-25, edition 2.0) "Universal serial bus interfaces for data and power – Part 1-3: Common components – USB Type-C Cable and Connector Specification"
* IEC 62680-1-3:2018 (2018-05-24, edition 3.0) "Universal serial bus interfaces for data and power – Part 1-3: Common components – USB Type-C Cable and Connector Specification"

#### Receptacles

The receptacle features four power and four ground pins, two differential pairs (connected together on devices) for legacy USB 2.0 high-speed data, four shielded differential pairs for Enhanced SuperSpeed data (two transmit and two receive pairs), two Sideband Use (SBU) pins, and two Configuration Channel (CC) pins.
Type-C receptacle A pin layout :
| Pin | Name | Description |
| A1 | GND | Ground return |
| A2 | SSTXp1 ("TX1+") | SuperSpeed differential pair #1, transmit, positive |
| A3 | SSTXn1 ("TX1−") | SuperSpeed differential pair #1, transmit, negative |
| A4 | V$_{BUS}$ | Bus power |
| A5 | CC1 | Configuration channel |
| A6 | D+ | USB 2.0 differential pair, position 1, positive |
| A7 | D− | USB 2.0 differential pair, position 1, negative |
| A8 | SBU1 | Sideband use (SBU) |
| A9 | V$_{BUS}$ | Bus power |
| A10 | SSRXn2 ("RX2−") | SuperSpeed differential pair #4, receive, negative |
| A11 | SSRXp2 ("RX2+") | SuperSpeed differential pair #4, receive, positive |
| A12 | GND | Ground return |
Type-C receptacle B pin layout :
| Pin | Name | Description |
| B12 | GND | Ground return |
| B11 | SSRXp1 ("RX1+") | SuperSpeed differential pair #2, receive, positive |
| B10 | SSRXn1 ("RX1−") | SuperSpeed differential pair #2, receive, negative |
| B9 | V$_{BUS}$ | Bus power |
| B8 | SBU2 | Sideband use (SBU) |
| B7 | D− | USB 2.0 differential pair, position 2, negative |
| B6 | D+ | USB 2.0 differential pair, position 2, positive |
| B5 | CC2 | Configuration channel |
| B4 | V$_{BUS}$ | Bus power |
| B3 | SSTXn2 ("TX2−") | SuperSpeed differential pair #3, transmit, negative |
| B2 | SSTXp2 ("TX2+") | SuperSpeed differential pair #3, transmit, positive |
| B1 | GND | Ground return |
* 1 2 There is only a single non-SuperSpeed differential pair in the cable. If this pin is not connected in the plug/cable, reversing the connector does not work. If this pin is connected in common in the plug with the corresponding A side pins, reversing the connector does work.

#### Plugs

The plug has only one USB 2.0 high-speed differential pair, and one of the CC pins (CC2) is replaced by V$_{CONN}$, to power optional electronics in the cable, and the other is used to actually carry the Configuration Channel (CC) signals. These signals are used to determine the orientation of the cable, as well as to carry USB Power Delivery communications.

#### Cables

Although plugs have 24 pins, cables have only 18 wires. In the following table, the "No." column shows the wire number.
Full-Featured USB 3.2 and 2.0 Type-C cable wiring :
| Plug 1, USB Type-C | Plug 1, USB Type-C | USB Type-C cable | USB Type-C cable | USB Type-C cable | USB Type-C cable | USB Type-C cable | Plug 2, USB Type-C | Plug 2, USB Type-C |
| Pin | Name | Wire color | No. | Name | Description | 2.0 | Pin | Name |
| Shell | Shield | Braid | Braid | Shield | Cable external braid | | Shell | Shield |
| A1, B12, B1, A12 | GND | Tin-plated | 1 | GND_PWRrt1 | Ground for power return | | A1, B12, B1, A12 | GND |
| A1, B12, B1, A12 | GND | Tin-plated | 16 | GND_PWRrt2 | Ground for power return | | A1, B12, B1, A12 | GND |
| A4, B9, B4, A9 | V$_{BUS}$ | Red | 2 | PWR_V$_{BUS}$1 | V$_{BUS}$ power | | A4, B9, B4, A9 | V$_{BUS}$ |
| A4, B9, B4, A9 | V$_{BUS}$ | Red | 17 | PWR_V$_{BUS}$2 | V$_{BUS}$ power | | A4, B9, B4, A9 | V$_{BUS}$ |
| B5 | V$_{CONN}$ | Yellow | 18 | PWR_V$_{CONN}$ | V$_{CONN}$ power, for powered cables | | B5 | V$_{CONN}$ |
| A5 | CC | Blue | 3 | CC | Configuration channel | | A5 | CC |
| A6 | D+ | Green | 4 | UTP_Dp | Unshielded twisted pair, positive | | A6 | D+ |
| A7 | D− | White | 5 | UTP_Dn | Unshielded twisted pair, negative | | A7 | D− |
| A8 | SBU1 | Red | 14 | SBU_A | Sideband use A | | B8 | SBU2 |
| B8 | SBU2 | Black | 15 | SBU_B | Sideband use B | | A8 | SBU1 |
| A2 | SSTXp1 | Yellow | 6 | SDPp1 | Shielded differential pair #1, positive | | B11 | SSRXp1 |
| A3 | SSTXn1 | Brown | 7 | SDPn1 | Shielded differential pair #1, negative | | B10 | SSRXn1 |
| B11 | SSRXp1 | Green | 8 | SDPp2 | Shielded differential pair #2, positive | | A2 | SSTXp1 |
| B10 | SSRXn1 | Orange | 9 | SDPn2 | Shielded differential pair #2, negative | | A3 | SSTXn1 |
| B2 | SSTXp2 | White | 10 | SDPp3 | Shielded differential pair #3, positive | | A11 | SSRXp2 |
| B3 | SSTXn2 | Black | 11 | SDPn3 | Shielded differential pair #3, negative | | A10 | SSRXn2 |
| A11 | SSRXp2 | Red | 12 | SDPp4 | Shielded differential pair #4, positive | | B2 | SSTXp2 |
| A10 | SSRXn2 | Blue | 13 | SDPn4 | Shielded differential pair #4, negative | | B3 | SSTXn2 |
* ↑ USB 2.0 Type-C cables do not include wires for SuperSpeed or sideband use.
* ↑ V$_{CONN}$ must not traverse end-to-end through the cable. Some isolation method must be used.
* 1 2 There is only a single differential pair for non-SuperSpeed data in the cable, which is connected to A6 and A7. Contacts B6 and B7 should not be present in the plug.
* 1 2 3 4 5 6 7 8 Wire colors for differential pairs are not mandated.

### Related USB-IF specifications
#### USB Type-C Locking Connector Specification

    The USB Type-C Locking Connector Specification was published 2016-03-09. It defines the mechanical requirements for USB-C plug connectors and the guidelines for the USB-C receptacle mounting configuration to provide a standardized screw lock mechanism for USB-C connectors and cables.

#### USB Type-C Port Controller Interface Specification

    The USB Type-C Port Controller Interface Specification was published 2017-10-01. It defines a common interface from a USB-C Port Manager to a simple USB-C Port Controller.

#### USB Type-C Authentication Specification

    Adopted as IEC specification: IEC 62680-1-4:2018 (2018-04-10) "Universal Serial Bus interfaces for data and power – Part 1-4: Common components – USB Type-C Authentication Specification"

#### USB 2.0 Billboard Device Class Specification

    USB 2.0 Billboard Device Class is defined to communicate the details of supported Alternate Modes to the computer host OS. It provides user readable strings with product description and user support information. Billboard messages can be used to identify incompatible connections made by users. They optionally appear to negotiate multiple Alternate Modes and must appear when negotiation fails between the host (source) and device (sink).

#### USB Audio Device Class 3.0 Specification

    USB Audio Device Class 3.0 defines powered digital audio headsets with a USB-C plug. The standard supports the transfer of both digital and analog audio signals over the USB port.

#### USB Power Delivery Specification

    Main article: USB Power Delivery While it is not necessary for USB-C compliant devices to implement USB Power Delivery, for USB-C DRP/DRD (Dual-Role-Power/Data) ports, USB Power Delivery introduces commands for altering a port's power or data role after the roles have been established when a connection is made.

#### USB 3.2 Specification

    USB 3.2, released in September 2017, replaces the USB 3.1 specification. It preserves existing USB 3.1 SuperSpeed and SuperSpeed+ data modes and introduces two new SuperSpeed+ transfer modes over the USB-C connector using two-lane operation, doubling the signalling rates to 10 and 20 Gbit/s (raw data rate 1 and ~2.4 GB/s). USB 3.2 is only supported by USB-C, making previously used USB connectors obsolete.

#### USB4 Specification

    The USB4 specification released in 2019 is the first USB data transfer specification to be exclusively applicable by the Type-C connector.

### Alternate Mode partner specifications

As of 2018, five system-defined Alternate Mode partner specifications exist. Additionally, vendors may support proprietary modes for use in dock solutions. Alternate Modes are optional; Type-C features and devices are not required to support any specific Alternate Mode. The USB Implementers Forum is working with its Alternate Mode partners to make sure that ports are properly labelled with respective logos.
List of Alternate Mode partner specifications :
| Name | Date | Protocol | Status |
| Thunderbolt Alternate Mode | Announced in June 2015 | USB-C is the native (and only) connector for Thunderbolt 3 and later Thunderbolt 3 (also carries 4× PCI Express 3.0, DisplayPort 1.2, DisplayPort 1.4, USB 3.1 Gen 2), Thunderbolt 4 (also carries 4× PCI Express 3.0, DisplayPort 2.0, USB4), Thunderbolt 5 (also carries 4× PCI Express 4.0, DisplayPort 2.1, USB4) | Current |
| DisplayPort Alternate Mode | Published in September 2014 | DisplayPort 1.2, DisplayPort 1.4, DisplayPort 2.0 | Current |
| Mobile High-Definition Link (MHL) Alternate Mode | Announced in November 2014 | MHL 1.0, 2.0, 3.0 and superMHL 1.0 | Current |
| HDMI Alternate Mode | Announced in September 2016 | HDMI 1.4b | Not being updated |
| VirtualLink Alternate Mode | Announced in July 2018 | VirtualLink 1.0 | Abandoned |
Other protocols like Ethernet have been proposed, although Thunderbolt 3 and later are also capable of 10 Gigabit Ethernet networking.
All Thunderbolt 3 controllers support both Thunderbolt Alternate Mode and DisplayPort Alternate Mode. Because Thunderbolt can encapsulate DisplayPort data, every Thunderbolt controller can either output DisplayPort signals directly over DisplayPort Alternative Mode or encapsulated within Thunderbolt in Thunderbolt Alternate Mode. Low-cost peripherals mostly connect via DisplayPort Alternate Mode while some docking stations tunnel DisplayPort over Thunderbolt.
DisplayPort Alternate Mode 2.0: DisplayPort 2.0 can run directly over USB-C alongside USB4. DisplayPort 2.0 can support 8K resolution at 60 Hz with HDR10 color and can use up to 80 Gbps, which is double the amount available to USB data.
The USB SuperSpeed protocol is similar to DisplayPort and PCIe/Thunderbolt, in using packetized data transmitted over differential LVDS lanes with embedded clock using comparable bit rates, so these Alternate Modes are easier to implement in the chipset.
Alternate Mode hosts and peripheral devices can be connected with either regular Full-Featured Type-C cables, or with converter cables or adapters:

#### USB 3.1 Type-C to Type-C Full-Featured cable

    DisplayPort, Mobile High-Definition Link (MHL), HDMI and Thunderbolt (20 Gbit/s, or 40 Gbit/s with cable length up to 0.5 m) Alternate Mode Type-C ports can be interconnected with standard passive Full-Featured USB Type-C cables. These cables are only marked with standard "trident" SuperSpeed USB logo (for Gen 1 mode only) or the SuperSpeed+ USB 10 Gbit/s logo on both ends. Cable length should be 2.0 m or less for Gen 1 and 1.0 m or less for Gen 2.

#### Thunderbolt Type-C to Type-C active cable

    Thunderbolt 3 (40 Gbit/s) Alternate Mode with cables longer than 0.8 m requires active Type-C cables that are certified and electronically marked for high-speed Thunderbolt 3 transmission, similarly to high-power 5 A cables. These cables are marked with a Thunderbolt logo on both ends. They do not support USB 3 backwards compatibility, only USB 2 or Thunderbolt. Cables can be marked for both Thunderbolt and 5 A power delivery at the same time.
Active cables and adapters contain powered electronics to allow for longer cables or to perform protocol conversion. The adapters for video Alternate Modes may allow conversion from native video stream to other video interface standards (e.g., DisplayPort, HDMI, VGA or DVI).
Using Full-Featured Type-C cables for Alternate Mode connections provides some benefits. Alternate Mode does not employ USB 2.0 lanes and the configuration channel lane, so USB 2.0 and USB Power Delivery protocols are always available. In addition, DisplayPort and MHL Alternate Modes can transmit on one, two, or four SuperSpeed lanes, so two of the remaining lanes may be used to simultaneously transmit USB 3.1 data.
Alternate Mode protocol support matrix for Type-C cables and adapters :
| Mode | USB 3.1 Type-C cable | USB 3.1 Type-C cable | USB 3.1 Type-C cable | USB 3.1 Type-C cable | USB 3.1 Type-C cable | USB 3.1 Type-C cable | USB 3.1 Type-C cable | Adapter cable or adapter | Adapter cable or adapter | Adapter cable or adapter | Adapter cable or adapter | Adapter cable or adapter | Construction |
| Mode | USB | DisplayPort | DisplayPort | Thunderbolt | Thunderbolt | superMHL | HDMI | HDMI | HDMI | DVI-D | DVI-D | Component video | Construction |
| Mode | 3.1 | 1.2 | 1.4 | 20 Gbit/s | 40 Gbit/s | superMHL | 1.4b | 1.4b | 2.0b | Single-link | Dual-link | (YPbPr, VGA/DVI-A) | Construction |
| DisplayPort | Yes | Yes | Yes | Does not appear | Does not appear | Does not appear | Does not appear | No | No | No | No | No | Passive |
| DisplayPort | Does not appear | Optional | Optional | Does not appear | Does not appear | Does not appear | Does not appear | Yes | Yes | Yes | Yes | Yes | Active |
| Thunderbolt | Yes | Yes | Yes | Yes | Yes | Does not appear | Does not appear | No | No | No | No | No | Passive |
| Thunderbolt | Does not appear | Optional | Optional | Optional | Yes | Does not appear | Does not appear | Yes | Yes | Yes | Yes | Yes | Active |
| MHL | Yes | Does not appear | Does not appear | Does not appear | Does not appear | Yes | Does not appear | Yes | No | Yes | No | No | Passive |
| MHL | Does not appear | Does not appear | Does not appear | Does not appear | Does not appear | Optional | Does not appear | Does not appear | Yes | Does not appear | Does not appear | Yes | Active |
| HDMI | Does not appear | Does not appear | Does not appear | Does not appear | Does not appear | Does not appear | Yes | Yes | No | Yes | No | No | Passive |
| HDMI | Does not appear | Does not appear | Does not appear | Does not appear | Does not appear | Does not appear | Optional | Does not appear | Does not appear | Does not appear | Does not appear | Yes | Active |
* ↑ USB 2.0 and USB Power Delivery are available at all times in a Type-C cable
* ↑ USB 3.1 can be transmitted simultaneously when the video signal bandwidth requires two or fewer lanes.
* 1 2 Is only available in Thunderbolt 3 DisplayPort mode
* ↑ Thunderbolt 3 40 Gbit/s passive cables are only possible <0.8 m due to limitations of current cable technology.

## USB-C receptacle pin usage in different modes

The diagrams below depict the pins of a USB-C receptacle in different use cases.

### USB 2.0/1.1

A simple USB 2.0/1.1 device mates using one pair of D+/D− pins. Hence, the source (host) does not require any connection management circuitry, but it lacks the same physical connector so therefore USB-C is not backward compatible. V$_{BUS}$ and GND provide 5 V up to 500 mA of current.
However, to connect a USB 2.0/1.1 device to a USB-C host, use of pull-down resistors Rd on the CC pins is required, as the source (host) will not supply V$_{BUS}$ until a connection is detected through the CC pins.
This means many USB-A–to–USB-C cables will only work in the A to C direction (connecting to a USB-C devices, e.g. for charging) as they do not include the termination resistors needed to work in the C to A direction (from a USB-C host). Adapters or cables from USB-C to a USB-A receptacle usually do work as they include the required termination resistor.
| GND | TX1+ | TX1− | V$_{BUS}$ | CC1 | D+ | D− | SBU1 | V$_{BUS}$ | RX2− | RX2+ | GND |
| GND | RX1+ | RX1− | V$_{BUS}$ | SBU2 | D− | D+ | CC2 | V$_{BUS}$ | TX2− | TX2+ | GND |

### USB Power Delivery

The USB Power Delivery specification uses one of CC1 or CC2 pins for power negotiation between source device and sink device, up to 20 V at 5 A. It is transparent to any data transmission mode, and can therefore be used together with any of them as long as the CC pins are intact.
An extension to the specification has added 28 V, 36 V and 48 V to support up to 240 W of power for laptops, monitors, hard disks and other peripherals.
| GND | TX1+ | TX1− | V$_{BUS}$ | CC1 | D+ | D− | SBU1 | V$_{BUS}$ | RX2− | RX2+ | GND |
| GND | RX1+ | RX1− | V$_{BUS}$ | SBU2 | D− | D+ | CC2 | V$_{BUS}$ | TX2− | TX2+ | GND |

### USB 3.0/3.1/3.2

In the USB 3.0/3.1/3.2 mode, two or four high speed links are used in TX/RX pairs to provide 5, 10, or 20 Gbit/s (only by USB 3.2 x2 two-lane operations) signalling rates respectively. One of the CC pins is used to negotiate the mode.
V$_{BUS}$ and GND provide 5 V up to 900 mA, in accordance with the USB 3.1 specification. A specific USB-C mode may also be entered, where 5 V at nominal either 1.5 A or 3 A is provided. A third alternative is to establish a USB Power Delivery (USB-PD) contract.
In single-lane mode, only the differential pairs closest to the CC pin are used for data transmission. For dual-lane data transfers, all four differential pairs are in use.
The D+/D− link for USB 2.0/1.1 is typically not used when a USB 3.x connection is active, but devices like hubs open simultaneous 2.0 and 3.x uplinks in order to allow operation of both types of devices connected to it. Other devices may have the ability to fall back to 2.0, in case the 3.x connection fails. For this, it is important that SS and HS lanes are correctly aligned so that i.e. operating system messages indicating overcurrent conditions report the correct shared USB plug.
| GND | TX1+ | TX1− | V$_{BUS}$ | CC1 | D+ | D− | SBU1 | V$_{BUS}$ | RX2− | RX2+ | GND |
| GND | RX1+ | RX1− | V$_{BUS}$ | SBU2 | D− | D+ | CC2 | V$_{BUS}$ | TX2− | TX2+ | GND |

### Alternate Modes

In Alternate Modes one of up to four high speed links are used in whatever direction is needed. SBU1, SBU2 provide an additional lower speed link. If two high speed links remain unused, then a USB 3.0/3.1 link can be established concurrently to the Alternate Mode. One of the CC pins is used to perform all the negotiation. An additional low band bidirectional channel (other than SBU) may share that CC pin as well. USB 2.0 is also available through D+/D− pins.
In regard to power, the devices are supposed to negotiate a Power Delivery contract before an Alternate Mode is entered.
| GND | TX1+ | TX1− | V$_{BUS}$ | CC1 | D+ | D− | SBU1 | V$_{BUS}$ | RX2− | RX2+ | GND |
| GND | RX1+ | RX1− | V$_{BUS}$ | SBU2 | D− | D+ | CC2 | V$_{BUS}$ | TX2− | TX2+ | GND |

### Debug Accessory Mode

The external device test system (DTS) signals to the target system (TS) to enter debug accessory mode via CC1 and CC2 both being pulled down with an Rd resistor value or pulled up as Rp resistor value from the test plug (Rp and Rd defined in Type-C specification).
After entering debug accessory mode, optional orientation detection via the CC1 and CC2 is done via setting CC1 as a pullup of Rd resistance and CC2 pulled to ground via Ra resistance (from the test system Type-C plug). While optional, orientation detection is required if USB Power Delivery communication is to remain functional.
In this mode, all digital circuits are disconnected from the connector, and the 14 bold pins can be used to expose debug related signals (e.g. JTAG interface). USB IF requires for certification that security and privacy consideration and precaution has been taken and that the user has actually requested that debug test mode be performed.
| GND | TX1+ | TX1− | V$_{BUS}$ | CC1 | D+ | D− | SBU1 | V$_{BUS}$ | RX2− | RX2+ | GND |
| GND | RX1+ | RX1− | V$_{BUS}$ | SBU2 | D− | D+ | CC2 | V$_{BUS}$ | TX2− | TX2+ | GND |
If a reversible Type-C cable is required but Power Delivery support is not, the test plug will need to be arranged as below, with CC1 and CC2 both being pulled down with an Rd resistor value or pulled up as Rp resistor value from the test plug:
| GND | TS1 | TS2 | V$_{BUS}$ | CC1 | TS6 | TS7 | TS5 | V$_{BUS}$ | TS4 | TS3 | GND |
| GND | TS3 | TS4 | V$_{BUS}$ | TS5 | TS7 | TS6 | CC2 | V$_{BUS}$ | TS2 | TS1 | GND |
This mirroring of test signals will only provide 7 test signals for debug usage instead of 14, but with the benefit of minimizing extra parts count for orientation detection.

### Audio Adapter Accessory Mode

In this mode, all digital circuits are disconnected from the connector, and certain pins become reassigned for analog outputs or inputs. The mode, if supported, is entered when both CC pins are shorted to GND. D− and D+ become audio output left L and right R, respectively. The SBU pins become a microphone pin MIC, and the analog ground AGND, the latter being a return path for both outputs and the microphone. Nevertheless, the MIC and AGND pins must have automatic swap capability, for two reasons: firstly, the USB-C plug may be inserted either side; secondly, there is no agreement, which TRRS rings shall be GND and MIC, so devices equipped with a headphone jack with microphone input must be able to perform this swap anyway.
This mode also allows concurrent charging of a device exposing the analog audio interface (through V$_{BUS}$ and GND), however only at 5 V and 500 mA, as CC pins are unavailable for any negotiation.
| GND | TX1+ | TX1− | V$_{BUS}$ | CC1 | R | L | MIC | V$_{BUS}$ | RX2− | RX2+ | GND |
| GND | RX1+ | RX1− | V$_{BUS}$ | AGND | L | R | CC2 | V$_{BUS}$ | TX2− | TX2+ | GND |
Plug insertions detection is performed by the TRRS plug's physical plug detection switch. On plug insertions, this will pull down both CC and VCONN in the plug (CC1 and CC2 in the receptacle). This resistance must be less than 800 ohms which is the minimum "Ra" resistance specified in the USB Type-C specification). This is essentially a direct connection to USB digital ground.
TRRS rings wiring to Type-C plug (Figure A-2 of USB Type-C Cable and Connector Specification Release 1.3) :
| TRRS socket | Analog audio signal | USB Type-C plug |
| Tip | L | D− |
| Ring 1 | R | D+ |
| Ring 2 | Microphone/ground | SBU1 or SBU2 |
| Sleeve | Microphone/ground | SBU2 or SBU1 |
| DETECT1 | Plug presence detection switch | CC, VCONN |
| DETECT2 | Plug presence detection switch | GND |

## Software support

* Android from version 6.0 "Marshmallow" onwards works with USB 3.1 and USB-C.
* ChromeOS, starting with the Chromebook Pixel 2015, supports USB 3.1, USB-C, Alternate Modes, Power Delivery, and USB Dual-Role support.
* FreeBSD released the Extensible Host Controller Interface, supporting USB 3.0, with release 8.2
* iOS from version 12.1 (iPad Pro 3rd generation or later, iPad Air 4th generation or later, iPad Mini 6th generation or later, iPad 10th generation or later, iPhone 15 or later) onwards works with USB-C.
* NetBSD began supporting USB 3.0 with release 7.2
* Linux has supported USB 3.0 since kernel version 2.6.31 and USB version 3.1 since kernel version 4.6.
* OpenBSD began supporting USB 3.0 in version 5.7
* OS X Yosemite (macOS version 10.10.2), starting with the MacBook Retina early 2015, supports USB 3.1, USB-C, Alternate Modes, and Power Delivery.
* Windows 8.1 added USB-C and billboard support in an update.
* Windows 10 and Windows 10 Mobile support USB 3.1, USB-C, alternate modes, billboard device class, Power Delivery and USB Dual-Role.

## Authentication

USB Type-C Authentication is an extension to the USB-C protocol which can add security to the protocol.

## Hardware support
### USB-C devices

An increasing number of motherboards, notebooks, tablet computers, smartphones, hard disk drives, USB hubs and other devices released from 2014 onwards include the USB-C receptacles. However, the initial adoption of USB-C was limited by the high cost of USB-C cables and the wide use of Micro-USB chargers.

#### Video output

Currently, DisplayPort is the most widely implemented alternate mode, and is used to provide video output on devices that do not have standard-size DisplayPort or HDMI ports, such as smartphones and laptops. All Chromebooks with a USB-C port are required to support DisplayPort alternate mode in Google's hardware requirements for manufacturers. A USB-C multiport adapter converts the device's native video stream to DisplayPort/HDMI/VGA, allowing it to be displayed on an external display, such as a television set or computer monitor.
It is also used on USB-C docks designed to connect a device to a power source, external display, USB hub, and optional extra (such as a network port) with a single cable. These functions are sometimes implemented directly into the display instead of a separate dock, meaning a user connects their device to the display via USB-C with no other connections required.

### Compatibility issues
#### Power issues with cables

Many cables claiming to support USB-C are actually not compliant to the standard. These cables can, potentially, damage a device. There are reported cases of laptops being destroyed due to the use of non-compliant cables.
Some non-compliant cables with a USB-C connector on one end and a legacy USB-A plug or Micro-B receptacle (receptacles also usually being invalid on cables, but see known exceptions in the sections on Hosts and peripheral devices and Audio adapter accessory mode above) on the other end incorrectly terminate the Configuration Channel (CC) with a 10 kΩ pull-up to V$_{BUS}$ instead of the specification mandated 56 kΩ pull-up, causing a device connected to the cable to incorrectly determine the amount of power it is permitted to draw from the cable. Cables with this issue may not work properly with certain products, including Apple and Google products, and may even damage power sources such as chargers, hubs, or PC USB ports.
A defective USB-C cable or power source can cause a USB-C device to see and an incorrect and different "declared" voltage than what the source will actually deliver. This may result in an overvoltage on the VBUS pin.
Also due to the fine pitch of the USB-C receptacle, the VBUS pin from the cable may contact with the CC pin of the USB-C receptacle resulting in a short-to-VBUS electrical issue due to the fact that the VBUS pin is rated up to 20 V while the CC pins are rated up to 5.5 V.
To overcome these issues, USB Type-C port protection must be used between a USB-C connector and a USB-C Power Delivery controller.

#### Compatibility with audio adapters

The USB-C port can be used to connect wired accessories such as headphones.
There are two modes of audio output from devices: digital and analog. There are primarily two types of USB-C audio adapters: active, e.g. those with digital-to-analog converters (DACs), and passive, without electronics.
When an active set of USB-C headphones or adapter is used, digital audio is sent through the USB-C port. The conversion by the DAC and amplifier is done inside of the headphones or adapter, instead of on the phone. The sound quality is dependent on the headphones/adapter's DAC. Active adapters with a built-in DAC have near-universal support for devices that output digital and analog audio, adhering to the Audio Device Class 3.0 and Audio Adapter Accessory Mode specifications.
Examples of such active adapters include external USB sound cards and DACs that do not require special drivers, and USB-C to 3.5 mm headphone jack adapters by Apple, Google, Essential, Razer, HTC, and Samsung.
On the other hand, when a passive adapter is used, digital-to-analog conversion is done on the host device and analog audio is sent through the USB-C port. The sound quality is dependent on the phone's onboard DAC. Passive adapters are only compatible with devices that output analog audio, adhering to the Audio Adapter Accessory Mode specification.
USB-C to 3.5 mm audio adapters and USB sound cards compatibility :
| Output mode | Specification | Devices | USB-C adapters | USB-C adapters |
| Output mode | Specification | Devices | Active | Passive, without DACs |
| Digital audio | Audio Device Class 3.0 (digital audio) | Apple iPhone 15, Google Pixel 2, HTC U11, Essential Phone, Razer Phone, Samsung Galaxy Note 10, Samsung Galaxy S10 Lite, Sharp Aquos S2, Asus ZenFone 3, Bluedio T4S, Lenovo Tab 4, GoPro, MacBook | No conversion | Conversion unavailable |
| Analog audio | Audio Device Class 3.0 (digital audio)Audio Adapter Accessory Mode (analog audio) | Apple iPhone 15, Moto Z/Z Force, Moto Z2/Z2 Force/Z2 Play, Moto Z3/Z3 Play, Sony Xperia XZ2, Huawei Mate 10 Pro, Huawei P20/P20 Pro, Honor Magic2, LeEco, Xiaomi phones, OnePlus 6T, OnePlus 7/7 Pro/7T/7T Pro, Oppo Find X/Oppo R17/R17 Pro, ZTE Nubia Z17/Z18 | Conversion by adapter | Pass-through |

#### Compatibility with other fast-charging technology

In 2016, Benson Leung, an engineer at Google, pointed out that Quick Charge 2.0 and 3.0 technologies developed by Qualcomm are not compatible with the USB-C standard. Qualcomm responded that it is possible to make fast-charge solutions fit the voltage demands of USB-C and that there are no reports of problems; however, it did not address the standard compliance issue at that time. Later in the year, Qualcomm released Quick Charge 4, which it claimed was – as an advancement over previous generations – "USB Type-C and USB PD compliant".

#### Regulations for compatibility

In 2021, the European Commission proposed the use of USB-C as a universal charger. On 4 October 2022, the European Parliament voted in favor of the new law, Radio Equipment Directive 2022/2380, with 602 votes in favor, 13 against and 8 abstentions. The regulation requires that all new mobile phones, tablets, cameras, headphones, headsets, handheld video game consoles, portable speakers, e-readers, keyboards, mice, portable navigation systems, and earbuds sold in the European Union and supporting wired charging, would have to be equipped with a USB-C port and charge with a standard USB-C to USB-C cable by the end of 2024. Additionally, if these devices support fast charging, they must support USB Power Delivery. These regulations will extend to laptops by early 2026. To comply with these regulations, Apple Inc. replaced its proprietary Lightning connector with USB-C beginning with the iPhone 15 and AirPods Pro second generation, released in 2023. A first modified iPhone having USB-C connector was the result of a hack by Ken Pillonel.
In late December 2024, new EU regulations took effect, mandating USB-C charging ports for all small and medium-sized electronic devices sold in the EU, with laptops to follow by 2026. These rules were aimed at reducing waste and saving €250 million annually for consumers. Apple, which initially opposed the changes, had since adopted USB-C for its products. Additionally, consumers can opt not to receive a new charger with their device.