USB-C Pinout: Receptacle, Plug & Cable Wiring

A USB-C receptacle has 24 pins in two rows of 12, A1–A12 and B1–B12, laid out so the socket works either way up: 4 GND (A1, A12, B1, B12), 4 VBUS (A4, A9, B4, B9), 2 CC (A5, B5), two USB 2.0 D+/D− positions (A6/A7 and B6/B7), four high-speed pairs (TX1 A2/A3, RX1 B11/B10, TX2 B2/B3, RX2 A11/A10) and 2 SBU (A8, B8). Pin An and pin Bn always carry the same kind of signal, so turning the plug over lands every contact on a matching pin. The plug has one CC contact, uses the other position for VCONN, and leaves out B6 and B7, so a full-featured plug has 22 contacts. Everything below is from the USB Type-C Cable and Connector Specification, Release 2.5 (March 2026). For the plug shapes and sizes of every USB connector, see the USB Connector Types Chart.

USB-C pin diagram

Receptacle pin assignments (all 24 pins)

Reading the pin table

• Why An and Bn match. Row B is numbered in the opposite direction from row A, so position n in both rows holds the same kind of signal: turning the plug over swaps CC1 for CC2, TX1 for TX2 and RX1 for RX2. The port works out which way round the plug is from the CC pins and routes the high-speed signals to match.
• Two USB 2.0 positions, one pair in the cable. The receptacle has D+/D− at A6/A7 and again at B6/B7 so USB 2.0 works either way up. The specification allows a device to join A6 to B6 and A7 to B7 on its board, with each joining trace no longer than 3.5 mm. A USB-C cable carries only one D+/D− pair.
• Mating order. GND and VBUS contacts are longer and touch first; all other contacts touch second. In the specification's alternate contact design VBUS touches second and the signals third.
• VBUS and GND. All four VBUS pins are joined together in the plug and on the device's board, and so are all four GND pins. The receptacle is rated 5 A; standard cables are rated 3 A. A source's receptacle keeps VBUS switched off until a sink is attached, so a bare USB-C socket on a charger is normally dead.
• High-speed pairs. A port transmits on its TX pairs and receives on its RX pairs. USB 3.2 uses one pair set (one lane) or both (two lanes); USB4 normally uses both.
• SBU1 and SBU2 (sideband use) are reserved for uses defined by the USB Type-C specification, the USB4 specification, liquid detection and Alternate Modes. A port that uses none of these must leave them open or pull them down through no less than 950 kΩ.
• USB 2.0-only receptacles connect only GND, VBUS, CC1/CC2, both D+/D− positions and SBU1/SBU2 (Table 3-5); the high-speed positions are left unconnected, and SBU may be connected only for a defined purpose.

Which contacts each plug has

About the plug

• Only one CC contact (A5) is wired through the cable. The plug's B5 position is VCONN, which the source powers (3.0 to 5.5 V) to run the e-marker chip in an electronically marked cable. All full-featured cables are electronically marked; a USB 2.0 USB-C cable needs an e-marker only if it is rated above 3 A.
• The power-only plug is meant only for devices that take power (sinks); it has nine contacts: CC, four VBUS and four GND.
• A powered (e-marked) plug shows a resistance Ra of 800 Ω to 1.2 kΩ on its VCONN contact. That is how a source tells a cable apart from a device (5.1 kΩ Rd) on the CC pins.

USB-C to USB-C cable wiring

About the cable wiring

• Wire numbers follow Tables 3-6 and 3-10 of the specification. Wires 16 and 17 are optional second GND and VBUS wires; wire 18 (VCONN) is optional and depends on how the e-marker is built.
• The high-speed pairs cross over in the cable: what one plug sends on TX1 arrives at the other plug's RX1, and SBU1 at one end becomes SBU2 at the other. CC, VBUS, GND and D+/D− run straight through.
• A USB 2.0 USB-C cable has only wires 1–5 (and 18 if e-marked); every other plug contact is left open. A full-featured cable also needs a 10 nF bypass capacitor on VBUS at each end (rated 30 V, or 63 V for an EPR cable).
• The high-speed pairs are shielded (usually micro-coaxial) and the shield is joined to GND in both plugs; the D+/D− pair is normally an unshielded twisted pair. A typical full-featured cable is 4 to 6 mm thick.

CC pull-up (Rp): what the source advertises

Other CC terminations

Voltage the sink reads on CC

How the current advertisement works

• The source's Rp and the sink's 5.1 kΩ Rd form a voltage divider on CC. With nominal values and a 5 V pull-up, 56 kΩ gives 5 × 5.1 ÷ (56 + 5.1) = 0.42 V (Default), 22 kΩ gives 0.94 V (1.5 A) and 10 kΩ gives 1.69 V (3.0 A); each falls inside its band in the table above. The Voltage Divider Calculator works the same sum for other values.
• The voltage bands are the specification's worked example for a sink with Rd at ±10% (Table 4-36); a sink with a ±20% Rd can tell only connected from disconnected.
• A source may implement Rp as a resistor to 4.75–5.5 V, a resistor to 3.3 V or a current source, using the values in the Rp table for each.
• "Default USB power" means 500 mA for USB 2.0, 900 mA for single-lane USB 3.2 and 1,500 mA for dual-lane USB 3.2, unless BC 1.2 or USB PD says otherwise. See the USB Power Delivery Guide for what comes after CC.

What the source sees on CC1 and CC2

Legacy cables and adapters

• USB-A to USB-C cables (and USB-C to Micro-B receptacle adapters) carry Rp = 56 kΩ ± 5% from CC to VBUS inside the USB-C plug, so the USB-C device sees a source offering Default USB power. The tighter ±5% tolerance allows for voltage drop in the cable. The cable itself is rated 3 A because many non-standard chargers supply more than the USB default.
• A pull-up of 10 kΩ to 5 V in such a cable would advertise 3.0 A (see the Rp table) from a USB-A port that is only required to supply 500 or 900 mA. That is why the specification fixes the value.
• USB-C to USB-B, Mini-B or Micro-B cables carry Rd = 5.1 kΩ ± 20% in the USB-C plug, so the USB-C host sees a sink and turns VBUS on.
• Only the defined legacy cables and adapters are allowed. Adapters with a USB-C receptacle on a legacy plug (for example a USB-C socket on a USB-A plug) are explicitly not defined or allowed, because they let users build invalid and potentially unsafe connections. The defined adapters go the other way: a USB-C plug to a USB 3.1 Standard-A receptacle, or to a USB 2.0 Micro-B receptacle, each 0.15 m long at most.

Sources

• Every pin, wire and value on this page, and the diagram itself, is read from one dataset, assets/data/usb-specs.json. The USB Type-C specification was downloaded from usb.org and checked against its figures and tables on 6 October 2026; the divider voltages are calculated from the nominal resistor values.
• USB 3.0 Promoter Group, USB Type-C Cable and Connector Specification, Release 2.5, 2026 (usb.org). Used for: Receptacle and plug front views (Figures 2-1, 2-2); pin assignments (Tables 3-4, 3-5); cable assemblies and lengths (Tables 3-1, 3-2); cable wiring (Tables 3-10, 3-11); CC terminations Rp, Rd, Ra (Tables 4-27 to 4-29); CC states (Table 4-10); sink CC voltages (Table 4-36); power precedence (Table 4-19); Type-C Current (Table 4-20); EPR cables (section 3.11); revision history.
• USB 3.0 Promoter Group (USB-IF), USB Power Delivery Specification, Revision 3.2, Version 1.2 (corrected printing of 19 August 2026), 2026 (usb.org). Used for: SPR fixed supplies (Tables 3.1 to 3.3); PPS (Tables 3.4, 4.2, 6.13); SPR and EPR AVS (Tables 4.3, 4.4, 3.5, 3.6); Fixed Supply tolerance and PPS/AVS step sizes (Table 4.6); cable VDO current and voltage fields; 300 kbit/s BMC bit rate; revision history (Table A.1).
• USB 3.0 Promoter Group, Universal Serial Bus 3.2 Specification, Revision 1.1, 2022 (usb.org). Used for: Revision history (USB 3.0 12 November 2008, USB 3.1 26 July 2013, USB 3.2 22 September 2017); Gen 1 5 Gbps 8b/10b and Gen 2 10 Gbps 128b/132b; effective bandwidth (section 4.4.11); dual-lane operation on USB Type-C only (Tables 5-1, 5-2).