ChromeOS Compatible - Cable Specification v1.2

Version: 1.2
Last updated: 2024-11-08

Legend

Product Verb Development Action
"MUST" Mandatory product requirement
"SHOULD" Optional recommendation
"MAY" Nice to have

Requirements Scope

This specification document describes the criteria that ChromeOS Compatible cables meet. This specification should not be used for WWCB products, or a product designed and certified together with a Chromebook.

Passive cable types

This specification applies to USB cables with the following connector combinations:

  • USB-A (male) to USB-C (male)
  • USB-C (male) to USB-C (male)
  • USB-A (female) to USB-C (male)
  • micro-B (male) to USB-C (male)
  • DP (male) to DP (male)
  • HDMI (male) to HDMI (male)

Active cable types

This specification applies to cables with the following connector combinations:

  • USB-C (male) to USB-C (male)

Principles

ChromeOS Compatible cables:

  • Work with any ChromeOS device out of the box
  • Uphold a quality standard
  • Comply with international standards and local regulations for safety and efficiency.

Required Technologies

USB cables MUST be based on the following technologies:

  1. The USB cable MUST comply with the USB Type-C Specification R2.2 or later.
  2. If the cable supports better than USB2.0 speed or higher than 3-amp current, then it MUST comply with the USB Power Delivery R3.1 V1.7.

Prerequisite Certifications

  • The cable SHOULD be USB-IF Certified and discoverable on the public portal page.
  • If the cable reports Intel SVID, then the cable MAY be Intel approved with documentation. This applies only to USB4 Gen3 cables, Thunderbolt 3 cables, or Thunderbolt 4 cables.

Hardware and Visual Design Requirements

  • The cable MUST default to the most recent version of any connection protocol it supports.
  • The HDMI cable SHOULD implement HDMI Forum spec and pass HDMI Forum Compliance Test Suite for the HDMI version implemented.
  • The DisplayPort (DP) cable SHOULD implement VESA spec and pass VESA Link Layer and PHY conformance for the DP version implemented. VESA specifications are available to the VESA members for download at VESA Standards.

Logos

  • The USB cable SHOULD use USB-IF standardized power and data indication logos as indicated in their logo usage guidelines for cables.
  • The cable SHOULD follow the VESA, HDMI Logo marketing guidelines

USB-C Cable Hardware and Visual Design Requirements

USB-IF Certification

  • The USB cable SHOULD be USB-IF Certified
  • If an approved USB logo is used, then the cable MUST be USB-IF Certified
  • The cable SHOULD be discoverable on public portal page

Thunderbolt Logos

  • If the cable is certified for Thunderbolt 3 or Thunderbolt 4, then the cable MUST follow Intel guidelines for proper Thunderbolt logo usage.

USB Type-C Cable Requirements

Logos for USB-C to USB-C Cables

  • All USB 3.2 Gen 1 USB-C to USB-C cable SHOULD bear the appropriate USB-IF logos for the performance of the cable.
  • All USB 3.2 Gen 2 USB-C to USB-C cable SHOULD bear the appropriate USB-IF logos for the performance of the cable.
  • All USB4 Gen 3 USB-C to USB-C cable SHOULD bear the appropriate USB-IF logos for the performance of the cable.
  • All USB 2.0 USB-C to USB-C cables SHOULD bear a High-Speed USB Trident logo.
    • Rationale: Inconsistent use of logos is likely to cause user confusion.
  • The USB logo SHOULD indicate the cable's power capability.
  • The USB cable SHOULD follow the guidelines for USB Performance logos (refer to https://www.usb.org/logo-license/).

Identification

USB-C to USB-C Cables

  • USB-C to USB-C cables rated at 3A current and USB 2.0 performance only MAY have an eMarker.
    • All other kinds of USB-C to USB-C cables MUST contain an eMarker, with performance and current capability information properly identified.
  • If eMarked:
    • Cable eMarker MUST have vendor-specific VID and unique PID
    • eMarker MUST support Ra weakening
    • Ra weakening MUST correctly follow vRa-reattach after UnattachedWait.SRC state
      • Cables with Ra weakening that fail this may appear as a "fake Rd" on oscilloscope
    • Unless cable contains feature requiring power, MUST be marked "Vconn required = 0"
      • Example: cable contains built-in lights, volt+ammeter display, etc. requiring Vconn
      • If the cable is USB-C to USB-C active cable, the cable MUST be marked “Vconn required = 1”
  • If eMarker reports SVID Modes, they MUST be disclosed to WWCB.
    • Proprietary functions and/or Firmware-update via Manufacturer. Mode, and their purpose, MUST be disclosed.
    • Intel SVID (Thunderbolt) MUST be appropriate for application and Intel approved
    • USB4 Gen3 cable MUST have Intel SVID for TBT3 backward compatibility
    • USB4 Gen4 cable MUST have Intel SVID for TBT3 backward compatibility
    • The active cables MUST contain SVIDs for the following
      • DP Alt Mode (0xFF01)
      • Intel SVID (Thunderbolt ) (0x8087)

Hardware Requirements

USB Type-C passive cable specifications

  • Cable plug dimensions MUST comply with USB-IF specifications.
  • The cable SHOULD use USB-IF Certified components and connectors.
  • If intended for data+video and "Full Featured":
    • If <=0.8m, strongly recommended to be USB4 Gen3 (40gbps)
    • If >0.8m and <=1m, strongly recommended to be USB3.2 Gen2 (20gbps) or USB4 Gen2 (20 gbps)
    • If >1m and <=2m, strongly recommended to be USB3.2 Gen1 (5gbps)
    • The above lengths are informative per Type-C R2.0 spec based on current technological limits.
      • See USB Type-C Specification Section 3.1.2, Table 3-1 USB Type-C Standard Cable Assemblies and Section 5.4, Table 5-1 Certified Cables Where USB4-compatible Operation is Expected for more details.
  • Products exceeding these technological limitations are permitted if USB-IF Certified.
    • "The cable lengths listed in the table are informative and represents the practical length based on cable performance requirements."

USB Type-C active cable specifications

  • The cable MUST be either TBT 4/5 certified or USB-IF certified
  • USB Type-C Active Cables MUST support the following modes
    • USB 3.2 operation at Gen 1 (5Gbps), Gen 2 (10Gbps) in 1 or 2 lane configuration
    • DisplayPort Alternate Mode with a minimum DisplayPort protocol support of DP 1.4 HBR3
    • USB4 Gen 2 and Gen 3 (Gen 4 optional)
    • Thunderbolt 3 Gen 2 and Gen 3
  • Recommended Active Cable Technologies
    • Linear ReDriver (LRD)
    • Active Retimer

USB Type-C Legacy Cable and Adapter Requirements

  • USB-A (male) to USB-C (male)
    • MUST have a single 56 KΩ pull-up resistor connecting Vbus and CC pin in the USB-C plug.
    • Cable MUST either be rated for USB 2.0 or USB 3.2 Gen 1/2, having the appropriate number of data carrying wires
    • If the cable is capable of USB 3.2 Gen 1/2, the USB-A plug MUST be the USB 3.1 USB Type-A plug with 9 pins.
    • If the cable is only capable of USB 2.0, the USB-A plug MUST be the USB 2.0 USB Type-A plug with 4 pins.
  • USB-A (female) to USB-C (male)
    • MUST have a single 5.1 KΩ pull-down resistor connecting Gnd and CC pin in the USB-C plug.
    • Adapter MUST be rated for USB 3.1 Gen 1.
    • USB-A receptacle MUST be a USB 3.1 Standard-A Receptacle with 9 pins.
  • micro-B (male) to USB-C (male)
    • MUST have a single 5.1 KΩ pull-down resistor connecting Gnd and CC pin in the USB-C plug.
    • Cable MUST either be rated for USB 2.0 or USB 3.2 Gen 1/2, having the appropriate number of data carrying wires
    • If the cable is capable of USB 3.2 Gen 1/2, the Micro-B plug MUST be the USB 3.1 USB Micro-B plug with 10 pins.
    • If the cable is only capable of USB 2.0, the Micro-B plug MUST be the USB 2.0 USB Micro-B plug with 5 pins.

Revision History

Date Version Notes
024-11-08 1.2 Include prerequisites for DP and HDMI cables
2024-10-24 1.1 Include active cable requirements for type-c
2024-02-01 1.0.1 Republication on a new platform
2023-10-11 1.0 Initial Partner Site Publication