Side by side

USB 3.0 19-pin versus USB Key-A 20-pin front-panel headers

Which motherboard front-panel USB header form does the board and case cable specify?

Computer-generated illustration, not a photograph. — P263 · ConnectorUSB 3.0 front-panel 19-pin internal connector

How they differ

USB 3.0 front-panel 19-pin internal connector Identify the keyed two-row internal header and verify the motherboard manual; do not force a Key-A cable or external USB plug into this interface.
USB 3.1 front-panel Key-A 20-pin header Verify the Key-A housing/keying and motherboard documentation before choosing a front-panel cable; do not infer USB mode or charging capability from the header alone.

Then askWhich motherboard front-panel USB header form does the board and case cable specify?

At a glance

Source-scoped form facts; counts, variants and unknowns are distinct
Field	USB 3.0 front-panel 19-pin internal connector	USB 3.1 front-panel Key-A 20-pin header
Type	Connector	Connector
Family	USB	USB
Shape	internal header	internal header
Nominal contacts	19S283Source-backed nominal position/contact count: 19.	20S284Source-backed nominal position/contact count: 20.
Positions / cavity span	Not recordedNot recorded in a normalized source-scoped field. Consult the exact part/revision; no value inferred from illustrations.	Not recordedNot recorded in a normalized source-scoped field. Consult the exact part/revision; no value inferred from illustrations.
Contact rows	2 (B550-A PRO:JUSB3)S757Named source examples retain separate role, part, view and axis limits; values are not a universal family specification. B550-A PRO:JUSB3. Documented role: PCB header. IntelThinMiniITXRev1.2p.26claims2.54mmpitch forUSB3.0while mechanicalS828drawing remains unviewed after direct403. This conflicting number is not adopted.; No pitch measured from MSI schematic or drawing pixels. No printedJUSB3label claimed as visible board silkscreen.	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.
Connector role	header; PCB header (B550-A PRO:JUSB3)S283 · S292 · S757Named source examples retain separate role, part, view and axis limits; values are not a universal family specification. motherboard front-panel USB 3.0 internal header B550-A PRO:JUSB3. Documented role: PCB header. IntelThinMiniITXRev1.2p.26claims2.54mmpitch forUSB3.0while mechanicalS828drawing remains unviewed after direct403. This conflicting number is not adopted.; No pitch measured from MSI schematic or drawing pixels. No printedJUSB3label claimed as visible board silkscreen.	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.
Key distinction	This legacy internal USB header is not the same physical interface as the newer USB-IF Key-A front-panel connector for USB Type-C/front-panel use.	Key-A is a specific internal mating interface and must not be conflated with the older 19-pin USB 3.0 front-panel header or with external USB Type-A/Type-C connectors.

Full evidence ledger and sources ↓

Illustrations are computer-generated with prior AI visual review; independent technical and rights review pending. A comparison is not a compatibility verdict.

This comparison stays within one evidence layer.

All selected records are Connector records. Similar layer does not mean compatible, interchangeable or safe to mate.

Families represented: USB

The reference ledger

Read the same question across.

2 selected records · 13 fields
No score. No compatibility verdict.

On a narrow screen, scroll the table sideways or open the field-by-field reading view below. Illustrations are not a size comparison.

Comparison of selected field notes; source links accompany each documented specification
What you are comparing	P263 / ConnectorUSB 3.0 front-panel 19-pin internal connector Identification schematic · not to scale · drawing review pending	P264 / ConnectorUSB 3.1 front-panel Key-A 20-pin header Identification schematic · not to scale · drawing review pending
Layer	Connector	Connector
Key distinction	This legacy internal USB header is not the same physical interface as the newer USB-IF Key-A front-panel connector for USB Type-C/front-panel use.	Key-A is a specific internal mating interface and must not be conflated with the older 19-pin USB 3.0 front-panel header or with external USB Type-A/Type-C connectors.
Nominal contacts	19S283Source-backed nominal position/contact count: 19.	20S284Source-backed nominal position/contact count: 20.
Positions / cavity span	Not recordedNot recorded in a normalized source-scoped field. Consult the exact part/revision; no value inferred from illustrations.	Not recordedNot recorded in a normalized source-scoped field. Consult the exact part/revision; no value inferred from illustrations.
Populated contacts	Not recordedNot recorded in a normalized source-scoped field. Consult the exact part/revision; no value inferred from illustrations.	Not recordedNot recorded in a normalized source-scoped field. Consult the exact part/revision; no value inferred from illustrations.
Contact rows	2 (B550-A PRO:JUSB3)S757Named source examples retain separate role, part, view and axis limits; values are not a universal family specification. B550-A PRO:JUSB3. Documented role: PCB header. IntelThinMiniITXRev1.2p.26claims2.54mmpitch forUSB3.0while mechanicalS828drawing remains unviewed after direct403. This conflicting number is not adopted.; No pitch measured from MSI schematic or drawing pixels. No printedJUSB3label claimed as visible board silkscreen.	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	Not recordedNot recorded in a normalized source-scoped field. Consult the exact part/revision; no value inferred from illustrations.	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	Not recordedNot recorded in a normalized source-scoped field. Consult the exact part/revision; no value inferred from illustrations.	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; PCB header (B550-A PRO:JUSB3)S283 · S292 · S757Named source examples retain separate role, part, view and axis limits; values are not a universal family specification. motherboard front-panel USB 3.0 internal header B550-A PRO:JUSB3. Documented role: PCB header. IntelThinMiniITXRev1.2p.26claims2.54mmpitch forUSB3.0while mechanicalS828drawing remains unviewed after direct403. This conflicting number is not adopted.; No pitch measured from MSI schematic or drawing pixels. No printedJUSB3label claimed as visible board silkscreen.	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.
Coupling / latch	Not recordedNot recorded in a normalized source-scoped field. Consult the exact part/revision; no value inferred from illustrations.	Not recordedNot recorded in a normalized source-scoped field. Consult the exact part/revision; no value inferred from illustrations.
Keying / polarization	20position outline with pin20 absent;19loadedpins in published JUSB3drawing. (B550-A PRO:JUSB3)S757Named source examples retain separate role, part, view and axis limits; values are not a universal family specification. B550-A PRO:JUSB3. Documented role: PCB header. IntelThinMiniITXRev1.2p.26claims2.54mmpitch forUSB3.0while mechanicalS828drawing remains unviewed after direct403. This conflicting number is not adopted.; No pitch measured from MSI schematic or drawing pixels. No printedJUSB3label claimed as visible board silkscreen.	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.
Documented identification	19-position/contact recognition fact in the cited implementation.C263A	20-position/contact recognition fact in the cited implementation.C264A
Evidence	C263A → Independent review pending	C264A → Independent review pending

Read field by field — no sideways scrolling

The same selected records, fields, values and source links as the table. Missing fields remain non-equivalent; no values are merged.

Layer

USB 3.0 front-panel 19-pin internal connectorP263 / Connector: Connector
USB 3.1 front-panel Key-A 20-pin headerP264 / Connector: Connector

Key distinction

USB 3.0 front-panel 19-pin internal connectorP263 / Connector: This legacy internal USB header is not the same physical interface as the newer USB-IF Key-A front-panel connector for USB Type-C/front-panel use.
USB 3.1 front-panel Key-A 20-pin headerP264 / Connector: Key-A is a specific internal mating interface and must not be conflated with the older 19-pin USB 3.0 front-panel header or with external USB Type-A/Type-C connectors.

Nominal contacts

USB 3.0 front-panel 19-pin internal connectorP263 / Connector: 19S283Source-backed nominal position/contact count: 19.
USB 3.1 front-panel Key-A 20-pin headerP264 / Connector: 20S284Source-backed nominal position/contact count: 20.

Positions / cavity span

USB 3.0 front-panel 19-pin internal connectorP263 / Connector: Not recordedNot recorded in a normalized source-scoped field. Consult the exact part/revision; no value inferred from illustrations.
USB 3.1 front-panel Key-A 20-pin headerP264 / Connector: Not recordedNot recorded in a normalized source-scoped field. Consult the exact part/revision; no value inferred from illustrations.

Populated contacts

USB 3.0 front-panel 19-pin internal connectorP263 / Connector: Not recordedNot recorded in a normalized source-scoped field. Consult the exact part/revision; no value inferred from illustrations.
USB 3.1 front-panel Key-A 20-pin headerP264 / Connector: Not recordedNot recorded in a normalized source-scoped field. Consult the exact part/revision; no value inferred from illustrations.

Contact rows

USB 3.0 front-panel 19-pin internal connectorP263 / Connector: 2 (B550-A PRO:JUSB3)S757Named source examples retain separate role, part, view and axis limits; values are not a universal family specification. B550-A PRO:JUSB3. Documented role: PCB header. IntelThinMiniITXRev1.2p.26claims2.54mmpitch forUSB3.0while mechanicalS828drawing remains unviewed after direct403. This conflicting number is not adopted.; No pitch measured from MSI schematic or drawing pixels. No printedJUSB3label claimed as visible board silkscreen.
USB 3.1 front-panel Key-A 20-pin headerP264 / Connector: 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

USB 3.0 front-panel 19-pin internal connectorP263 / Connector: Not recordedNot recorded in a normalized source-scoped field. Consult the exact part/revision; no value inferred from illustrations.
USB 3.1 front-panel Key-A 20-pin headerP264 / Connector: 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

USB 3.0 front-panel 19-pin internal connectorP263 / Connector: Not recordedNot recorded in a normalized source-scoped field. Consult the exact part/revision; no value inferred from illustrations.
USB 3.1 front-panel Key-A 20-pin headerP264 / Connector: 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

USB 3.0 front-panel 19-pin internal connectorP263 / Connector: header; PCB header (B550-A PRO:JUSB3)S283 · S292 · S757Named source examples retain separate role, part, view and axis limits; values are not a universal family specification. motherboard front-panel USB 3.0 internal header B550-A PRO:JUSB3. Documented role: PCB header. IntelThinMiniITXRev1.2p.26claims2.54mmpitch forUSB3.0while mechanicalS828drawing remains unviewed after direct403. This conflicting number is not adopted.; No pitch measured from MSI schematic or drawing pixels. No printedJUSB3label claimed as visible board silkscreen.
USB 3.1 front-panel Key-A 20-pin headerP264 / Connector: 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.

Coupling / latch

USB 3.0 front-panel 19-pin internal connectorP263 / Connector: Not recordedNot recorded in a normalized source-scoped field. Consult the exact part/revision; no value inferred from illustrations.
USB 3.1 front-panel Key-A 20-pin headerP264 / Connector: Not recordedNot recorded in a normalized source-scoped field. Consult the exact part/revision; no value inferred from illustrations.

Keying / polarization

USB 3.0 front-panel 19-pin internal connectorP263 / Connector: 20position outline with pin20 absent;19loadedpins in published JUSB3drawing. (B550-A PRO:JUSB3)S757Named source examples retain separate role, part, view and axis limits; values are not a universal family specification. B550-A PRO:JUSB3. Documented role: PCB header. IntelThinMiniITXRev1.2p.26claims2.54mmpitch forUSB3.0while mechanicalS828drawing remains unviewed after direct403. This conflicting number is not adopted.; No pitch measured from MSI schematic or drawing pixels. No printedJUSB3label claimed as visible board silkscreen.
USB 3.1 front-panel Key-A 20-pin headerP264 / Connector: 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.

Documented identification

USB 3.0 front-panel 19-pin internal connectorP263 / Connector: 19-position/contact recognition fact in the cited implementation.C263A
USB 3.1 front-panel Key-A 20-pin headerP264 / Connector: 20-position/contact recognition fact in the cited implementation.C264A

Evidence

USB 3.0 front-panel 19-pin internal connectorP263 / Connector: C263A →
Independent review pending
USB 3.1 front-panel Key-A 20-pin headerP264 / Connector: C264A →
Independent review pending

Your next step

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Open the field notes Read source-linked facts and limitations.Compare another pair Start from a common confusion.Check a connection A comparison is not a compatibility verdict.

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Evidence behind this page

Scope first. Source second. Approval separate.

2 linked sources · 2 scoped claims · 0 sources with inspection/access flags.

Page scope: Evidence behind the compared records; the editorial comparison still needs separate review.

Assessment 2026-10-22 · earliest scheduled source review 2027-01-04. This is a recorded-date assessment, not a live source check. Page-level independent review is not established by this panel.

Inspect 2 source scopes, access limits and dates

S283 · Front Panel USB 3.0 Connector Pin-Out Signal Names

Intel · Manufacturer / product-owner domain · inspected 2026-10-06 · due 2027-01-04

Within inspection window

Scoped support: Documents motherboard-header pin numbers 1 through 19 for an Intel front-panel USB 3.0 connector; V43 uses only the populated-contact identity.

Not established / limitations: Identification/reference scope only. V43 does not convert this source into a universal pinout, fabrication drawing, electrical approval, protocol guarantee or end-to-end compatibility verdict.

Locator: Front-panel USB 3.0 connector table

S284 · USB 3.1 Front-Panel Internal Cable and Connector Implementation Document, Rev. 1.1

USB Implementers Forum · Standards-organization domain · inspected 2026-10-06 · due 2027-01-04

Within inspection window

Scoped support: Defines 20-pin and 40-pin front-panel internal headers; the 20-pin Key-A supports one USB Type-C port or one Standard-A port. V43 uses mechanical/interface identity only.

Locator: Section 2 / page 6, 20-pin Key-A header

Trace 2 claims to their source records

C263A · P263

Intel documents a front-panel USB 3.0 motherboard connector with populated pin positions numbered 1 through 19.

Claim scope: V43 catalogue-expansion identification fact only; not independent technical approval, fabrication data, wiring instruction, protocol guarantee or end-to-end compatibility proof.

Source links: S283 · Evidence trail → (private workspace)

C264A · P264

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.

Claim scope: V43 catalogue-expansion identification fact only; not independent technical approval, fabrication data, wiring instruction, protocol guarantee or end-to-end compatibility proof.

Source links: S284 · Evidence trail → (private workspace)

Prepare this page for review →Read the evidence method →

Recorded evidence only. An inspection date, publisher label, source link or generated packet is not independent technical review, hardware testing, fabrication approval or a compatibility verdict.