C264Asource checked
USB-IF defines a 20-pin Key-A front-panel internal header and states that it supports one USB Type-C port or one Standard-A port.
E264 · Source-scoped pinout variants
USB 3.1 front-panel Key-A 20-pin header engineering reference
USB-IF Revision 1.1 Key-A 20-pin reference design supporting one USB Type-C front-panel port. Key-A and Key-B are mechanically distinct, and the internal cable is not reversible/flip-able.
Source checked · no independent review claimed · Fabrication approved: no
source-scoped contact reference · independent review pending
Read the contact side, not a guessed mirror
This pilot uses the documented view for USB-IF Key-A header / one Type-C front-panel port. It is not a general pinout, device compatibility check, wiring instruction or fabrication drawing.
Source scopeUSB-IF implementation document Rev. 1.1
Reading directionLooking into the front of the 20-pin header
Contact mappingNumbered layout, within exact cited view
Verify next: Confirm the motherboard’s Key-A versus Key-B connector, exact port mode and cable requirements; an external reversible Type-C plug does not make this internal header reversible.
Show source locator, claim and unresolved limitations
C264B · open this page’s canonical claim — USB-IF Rev. 1.1 defines the Key-A 20-pin front-panel header as non-reversible and, looking into the front of the header for one USB Type-C port, assigns P1–P20 to VBUS, SuperSpeed pairs, ground, CC1/CC2, SBU1/SBU2 and D+/D− as shown in Figure 3-1.
S293 · USB Implementers Forum / source register · Read original source ↗
Source location: Sections 2.1, 2.3 and 3.2.1; Figure 3-1 on document page 19
Limitations: This profile covers the Key-A 20-pin reference design for one USB Type-C front-panel port. It does not certify a motherboard, cable assembly, USB mode, charging capability or fabricated part.
Profile unknowns: This Key-A contact assignment is the USB-IF one-Type-C-port reference design; it does not prove that a specific motherboard implements every USB mode, Alternate Mode or charging feature.
Rights: Linked specification and original normalized facts only. No USB-IF figures, tables or artwork redistributed. The indexed schematic is original, not a tracing of the source drawing.
Technical approval: pending · Rights approval: pending · Public release: withheld · Physical fit, polarity, voltage and device modes: not inferred.
Orientation
How to read this profile
Contact assignment is published looking into the front of the header: P1–P10 across the upper row and P20–P11 across the lower row in the USB-IF Figure 3-1 view.
Source-scoped identification facts
Each value retains its exact example, role and measurement axis. Facts from different parts must not be combined into an invented component.
| Nominal contacts | 20S284Source-backed nominal position/contact count: 20. |
|---|---|
| Contact rows | 2S829Named source examples retain separate role, part, view and axis limits; values are not a universal family specification. USB-IF2017 KeyA20pin shielded header reference. Documented role: socket. 13mm is shielded reference header span,not every vendor part. No manufacturer/part invented.; 19mm mated assembly and right-angle overmould reference maxima are excluded from bare header geometry.; USB-IFPDFmetadata inaccurately labelsPCMCIAProposal279;actualtitle/content checked asUSB3.1frontpanelRev1.1.; Required arrow is documented reference design scope,not an observed individual specimen. |
| Contact pitch | 0.8 mm row-longitudinal mating contact centerlineS829Named source examples retain separate role, part, view and axis limits; values are not a universal family specification. USB-IF2017 KeyA20pin shielded header reference. Documented role: socket. 13mm is shielded reference header span,not every vendor part. No manufacturer/part invented.; 19mm mated assembly and right-angle overmould reference maxima are excluded from bare header geometry.; USB-IFPDFmetadata inaccurately labelsPCMCIAProposal279;actualtitle/content checked asUSB3.1frontpanelRev1.1.; Required arrow is documented reference design scope,not an observed individual specimen. |
| Dimensions / axis | 13 ± 0.25 mm header shell horizontal span in front drawingS829Named source examples retain separate role, part, view and axis limits; values are not a universal family specification. USB-IF2017 KeyA20pin shielded header reference. Documented role: socket. 13mm is shielded reference header span,not every vendor part. No manufacturer/part invented.; 19mm mated assembly and right-angle overmould reference maxima are excluded from bare header geometry.; USB-IFPDFmetadata inaccurately labelsPCMCIAProposal279;actualtitle/content checked asUSB3.1frontpanelRev1.1.; Required arrow is documented reference design scope,not an observed individual specimen. |
| Connector role | header; socketS284 · S293 · S829Named source examples retain separate role, part, view and axis limits; values are not a universal family specification. USB-IF Key-A motherboard front-panel internal header USB-IF2017 KeyA20pin shielded header reference. Documented role: socket. 13mm is shielded reference header span,not every vendor part. No manufacturer/part invented.; 19mm mated assembly and right-angle overmould reference maxima are excluded from bare header geometry.; USB-IFPDFmetadata inaccurately labelsPCMCIAProposal279;actualtitle/content checked asUSB3.1frontpanelRev1.1.; Required arrow is documented reference design scope,not an observed individual specimen. |
| Keying / polarization | KeyAplug mates only corresponding KeyAheader;KeyB is distinct;internal cable not reversible.S829Named source examples retain separate role, part, view and axis limits; values are not a universal family specification. USB-IF2017 KeyA20pin shielded header reference. Documented role: socket. 13mm is shielded reference header span,not every vendor part. No manufacturer/part invented.; 19mm mated assembly and right-angle overmould reference maxima are excluded from bare header geometry.; USB-IFPDFmetadata inaccurately labelsPCMCIAProposal279;actualtitle/content checked asUSB3.1frontpanelRev1.1.; Required arrow is documented reference design scope,not an observed individual specimen. |
| Series | USB-IF2017 KeyA20pin shielded header referenceS829Named source examples retain separate role, part, view and axis limits; values are not a universal family specification. USB-IF2017 KeyA20pin shielded header reference. Documented role: socket. 13mm is shielded reference header span,not every vendor part. No manufacturer/part invented.; 19mm mated assembly and right-angle overmould reference maxima are excluded from bare header geometry.; USB-IFPDFmetadata inaccurately labelsPCMCIAProposal279;actualtitle/content checked asUSB3.1frontpanelRev1.1.; Required arrow is documented reference design scope,not an observed individual specimen. |
| Recorded markings | Orientation arrow required on header and plug along length direction near pin3 per sec2.3item1.S829Named source examples retain separate role, part, view and axis limits; values are not a universal family specification. USB-IF2017 KeyA20pin shielded header reference. Documented role: socket. 13mm is shielded reference header span,not every vendor part. No manufacturer/part invented.; 19mm mated assembly and right-angle overmould reference maxima are excluded from bare header geometry.; USB-IFPDFmetadata inaccurately labelsPCMCIAProposal279;actualtitle/content checked asUSB3.1frontpanelRev1.1.; Required arrow is documented reference design scope,not an observed individual specimen. |
| View convention | Contact assignment is published looking into the front of the header: P1–P10 across the upper row and P20–P11 across the lower row in the USB-IF Figure 3-1 view.; Fig2-1dimensioned front header mating face;Fig3-1explicitly looks into front of header;plug interface separateFig2-5.S284 · S293 · S829Named source examples retain separate role, part, view and axis limits; values are not a universal family specification. Existing engineering orientation text; source/part/view remains controlling. USB-IF2017 KeyA20pin shielded header reference. Documented role: socket. 13mm is shielded reference header span,not every vendor part. No manufacturer/part invented.; 19mm mated assembly and right-angle overmould reference maxima are excluded from bare header geometry.; USB-IFPDFmetadata inaccurately labelsPCMCIAProposal279;actualtitle/content checked asUSB3.1frontpanelRev1.1.; Required arrow is documented reference design scope,not an observed individual specimen. |
Not recorded: Positions / cavity span, Populated contacts, Contact gender / arrangement, Mounting, Coupling / latch, Shell / form, Manufacturer, Exact part / implementation. Unknown fields stay unknown; illustrations supply no measurements or pin assignments.
Recorded variant and source limits
- This Key-A contact assignment is the USB-IF one-Type-C-port reference design; it does not prove that a specific motherboard implements every USB mode, Alternate Mode or charging feature.
- Reference mechanical dimensions remain in the linked specification and are not republished as fabrication approval.
- The internal interface is not reversible/flip-able even though an external USB Type-C plug is reversible.
- Key-A 20-pin header/plug wired to one USB Type-C port: Front of header, per Figure 3-1.
- Key-A 20-pin header/plug wired to one Standard-A port (subset): Front of header, per Figure 3-2.
- Key-A 20-pin header, one USB Type-C front port (USB-IF reference): Looking into the front of the header (Figure 3-1).
- Key-A 20-pin header/plug wired to one Standard-A front port (USB-IF reference): Looking into the front of the header (Figure 3-2).
Pins & wiring
Pinout
Choose the exact wiring. Pin numbers follow its stated view; a schematic does not establish physical positions. Check your exact device before wiring.
What the status labels mean
- Confirmed
- Recorded research passes agree within this variant; this is not independent human review or hardware validation.
- Single source
- Only one underlying document, or one pass, supports this assignment.
- Device-specific
- Supported for the named equipment or wiring only. Check your device’s manual.
- Unverified
- Missing or conflicting evidence. Do not wire from this row.
- Not connected
- The source explicitly says NC, no contact or no pin for this wiring.
Unknowns stay unknown.
- This Key-A contact assignment is the USB-IF one-Type-C-port reference design; it does not prove that a specific motherboard implements every USB mode, Alternate Mode or charging feature.
- Reference mechanical dimensions remain in the linked specification and are not republished as fabrication approval.
- The internal interface is not reversible/flip-able even though an external USB Type-C plug is reversible.
Your next step
Use the detail without guessing past its limits.
Source trail
Claims and sources
C264Bsource checked
USB-IF Rev. 1.1 defines the Key-A 20-pin front-panel header as non-reversible and, looking into the front of the header for one USB Type-C port, assigns P1–P20 to VBUS, SuperSpeed pairs, ground, CC1/CC2, SBU1/SBU2 and D+/D− as shown in Figure 3-1.
C809Psource checked
Key-A 20-pin header/plug wired to one USB Type-C port: original contact normalization. Statuses distinguish comparison agreement, source limits and named-device wiring.
C809Qsource checked
Key-A 20-pin header/plug wired to one Standard-A port (subset): original contact normalization. Statuses distinguish comparison agreement, source limits and named-device wiring.
C809Rsource checked
Key-A 20-pin header, one USB Type-C front port (USB-IF reference): original contact normalization. Statuses distinguish comparison agreement, source limits and named-device wiring.
C809Ssource checked
Key-A 20-pin header/plug wired to one Standard-A front port (USB-IF reference): original contact normalization. Statuses distinguish comparison agreement, source limits and named-device wiring.