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Difference between USB-C vs USB 3.1

Difference between USB-C vs USB 3.1

Black Box Explains

The USB Implementers Forum (USB-IF) recently renamed USB 3.0, the third comprehensive revisions of Universal Serial Bus (USB) into USB 3.1 Gen 1. In addition, USB 3.1 Gen 2 and the new connector and receptacle called USB Type C were introduced.

Read our small article to understand the capabilities of the new versions, types of connectors. Learn more about alternate modes and market trends of the USB technology.

USB 3.1 Technology

1 - USB 3.1 Gen 1 (Formally USB 3.0)

  • 5 Gbps Bandwidth
  • 3.4 Gbps effective throughput
  • 900mA power available to the downstream device
  • Full Duplex (vs. Half Duplex USB 2.0)
  • Supported as standard with latest macOS, Linux, and Windows Operating systems
  • Exists as a completely separate bus from USB 2.0
    USB 3.1 data and USB 2.0 data are completely separate, running on different conductors in the connector and cable

2 - USB 3.1 Gen 2

  • 10 Gbps Bandwidth
  • Supported typically through third party drivers and controllers (like AsMedia) and not standard on Intel/AMD hosts as of Jan 2017
  • Other minor protocol changes over USB 3.1 Gen 1, but maintains backwards compatibility

3 - USB 3.1 Applications

  • Mass Storage devices
    • Hard Drives, Blu-Ray Drives, Flash Drives
    • Massive increase in performance over USB 2.0
    • Consumers demanding faster devices to compensate for larger video and picture file sizes
  • Video Conferencing
    USB 3.1 PTZ Cameras capable of 1080p60 and beyond without the use of a hardware codec, decreasing the overall cost of implementation and allowing users to bring their own devices to connect to Skype, WebEx, etc.
  • Machine Vision
    USB Machine vision cameras provide cost effective solutions capable of high resolution and frame rates for product analysis on assembly lines

4 - USB 3.1 Connector Pinout

USB 3.0 and 3.1 connectors have additional connections to support the new SuperSpeed performance. D+ and D- connections remain the same, along with power and ground. In addition there are new twisted pair balanced drivers and receivers for the SuperSpeed data transfer. On the receiver side, they are called StdA_SSRX+ and StdA_SSRX-, on the transmitter side SSTX+ and StdA_SSTX.

Pin Label Wire
1 VBUS Red
2 D- White
3 D+ Green
4 GND Black
5 StdA_SSRX- Blue
6 StdA_SSRX+ Yellow
7 GND_DRAIN GROUND
8 StdA_SSTX- Purple
9 StdA_SSTX+ Orange

USB Type C Standard

1 - USB Type C Features

  • Defines a reversible connector capable of supporting Data rates up to 40 Gbps
    • 10 Gbps per lane, 4 lanes total
  • USB Type-C's connector and receptacle are smaller sized (comparable to Micro-USB) and more durable, withstanding 10,000 insertion/removal cycles. With symmetrical 24 pins, the connector will attach to the receptacle on the first try.
  • Up to 100W of power delivery
  • USB 2.0, 3.1 Gen 1, and 3.1 Gen 2 capable
  • Support for alternate modes, to allow for more than just USB data to be sent across the connector and cable assembly
  • Standard driven from computer and Mobile phone manufactures who needed a smaller better interface for USB.
  • Cables are electronically marked to allow for power delivery negotiation
    • This is done for safety reasons, to prevent too much power from going across a cable that cannot support it, although we have seen some bad exceptions get into the market causing damage
    • No More dumb cables!
  • USB-C ports may be providers or consumers of power
    • The same port used to connect your flash drive could also be used to charge your laptop.
    • The Power delivery mode charges smartphones and tablets much faster.
  • Cables and connectors will also have varying capabilities
  • e.g. - a port or cable may only support USB 2.0, and no power delivery
  • Identification of capabilities becomes important!

2 – USB Type C Alternate Modes

2.1 DisplayPort Alternate Mode

  • Supports up to 4Kp60 4:4:4 with DisplayPort 1.3 Spec
  • Simultaneous Support for USB 3.1 Gen 2 and USB 2.0
  • Power transfer up to 100W
  • First monitors introduced @ CES 2016

2.2 MHL (Mobil High-Definition Link) Alternate Modes

  • Supports up to 4Kp60 with a single lane of data, or 8Kp60 with 4 lanes with superMHL 1.0 specification
  • USB 2.0, 3.1 support depending on configuration
  • Power delivery up to 100W
  • Currently no devices on the market

2.3 Thunderbolt 3 Alternate Mode

  • Support for up to 2 displays running 4Kp60
  • Connecting PCIe 3.0, DisplayPort, and USB 2.0 and 3.1 protocols depending on configuration
  • Power delivery up to 100W
  • Laptops from Dell, Lenovo, Apple, HP have begun shipping with USB-C connectors supporting this alternate mode

2.4 HDMI Alternate Mode

  • Supports HDMI 1.4b spec (4Kp30, 4Kp60 4:2:0)
  • Cannot support simultaneous USB 3.1 data in any configuration (limited to USB 2.0)
  • Power delivery up to 100W
  • No devices currently on the market supporting this mode

3 – USB Type C Market Trends

  • Increasing adoption with Mobile Phones and Laptops
  • Common devices include:
    • Adapters to legacy connections (USB A/B, DVI, etc)
    • Flash Drives
    • Docking stations
    • Monitors
  • Expected roughly 500 million device shipments by 2017, 2 billion by 2019
    • Via IHS USB Type C Report 2015
    • Total of 2.5 billion devices shipped by 2020 according to Global Industry Analysts Inc. report 2015

USB Standards at a glance

USB Type Throughput Direction Pin Count
1.X 1.5 Mbit/s (Low speed),
12 Mbit/s (Full speed)
Half Duplex; Not reversible 4
2 480 Mbit/s (High Speed) Half Duplex; Not reversible 4-5
3 5 Gbit/s (SuperSpeed) Full Duplex; Not reversible 9
3.1/Gen2 10 Gbit/s (SuperSpeed+) Full Duplex; Not reversible 9
Type-C 10 Gbit/s (SuperSpeed+) Full Duplex; Reversible 24

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USB 3.1 inside Black Box

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