With the need for increasing capabilities, USB technology has evolved and improved over several years. Recently, the USB Implementation Forum has released the specifications for the SuperSpeed+1 standard or USB 3.1 Gen 2 signal standard and the USB Type C connector. Data transfer rates have been increasing from USB 1.0, released in January 1996, with a full speed of 1.5 MB/s, to USB 2.0, released in April 2000, with full speed of 60 MB/s, and to USB 3.0, released in Nov 2008, with a full speed of 625 MB/s. The latest standard, USB 3.1 Gen 2 was released in Jul 2013, and has a full speed of 1.25 GB/s.
Confusion between USB Type C and USB 3.1 Gen 2
When discussing the relationship, people are often confused between the USB Type C and the USB 3.1 Gen 2 standard. The major point to note is the USB Type C standard defines the physical connector alone, whereas the USB 3.1 Gen 2 standard defines the electrical signal for communication.
Therefore, system designers have the freedom to select signals conforming to USB 3.1 Gen 2 to pass through USB Type C connectors and cables or through a connector that do not conform to the USB Type C specification. Designers can implement their own proprietary connector and still use the USB 3.1 Gen 2 signal standard in case they want to use their own hardware or to ensure their system remains isolated from other systems.
The reverse is also equally true and applicable. One can use the USB Type C connector to transmit and receive signals that do not conform to the USB signal standards. Although the implementation will benefit from the inexpensive and easily available USB Type C connectors and cables, the OEM must label it correctly, since the user will be at the risk of connecting the proprietary non-conforming system to a USB 3.1 Gen 2 standard system and damaging one or both the systems.
OEMs can also transmit legacy USB signaling configurations using the USB Type C connectors and cables. This is because the USB standard allows using pre-USB 3.1 Gen 2 on USB Type C connectors, as they have designed the standard to cause no damage to either system. However, the most optimum power and data transfer will occur only when both systems are negotiating a common power configuration and communication standard.
Why USB Type C
Compared to the older configurations, the use of the USB Type C connector offers several advantages. Apart from being a smaller package with more conductors, the USB Type C supports higher voltage and current ratings, while offering greater signal bandwidths.
Physically smaller, the USB Type C plugs and receptacles fit in a wide range of applications where space is restricted. Moreover, one can connect the plugs and receptacles any way—either right-side up or up-side down. This allows easier and faster insertions of plugs into their receptacles.
While USB Type A and B connectors can have a maximum of four or five conductors, there are 24 contacts within the USB Type C and it can carry 3 A at 5 V, or 15 W of power.
