Lifting the Veil from USB Type-C Bus

Since the launch in 1995, Universal Serial Bus (USB) has proved itself as the most successful ever computing interface. Nowadays tens of billions of electronic devices are connected together due to it. It goes without saying that this bus has outlived a few modifications, each distinguished by higher speed and reliability. Thus, today the community is able to revel in a completely new modification – USB Type-C – that forecasts a lot privileges of connectivity process. Let’s see what users will get with a new bus.

Layout and Connectivity

In physical terms, Type-C is a bit larger than USB 2.0 Micro-B but a bit tinier than binary USB 3.0 Micro-B, featuring 8.34x2.56 mm. Such dimensions enable its connection to the devices of any type, including the thinnest smartphones/tablets. The oval-shaped socket houses 24 contact outputs (to compare: USB 3.0 sockets feature only 9 outputs).

The most outstanding physical peculiarity of Type-C is a symmetric connector that allows for connecting the male to the socket by either side. This facility became possible thanks to the implementation of a unique commutation and coordination logics. Moreover, identical males are located on both sides of the interface cable. External coverage is absolutely blind, while connector is fixed by means of dedicated latches.

In keeping with the developer’s stats, Type-C’s MTBF index approximates 10.000 connections. At the same time, manufacturers underline that a new bus is not data transfer interface; this is rather a connector that unites various signal and power lines. To be precise, Type-C might support as USB 3.1, so 3.0/2.0 versions of the interface, depending on the installed controller.

Data Transfer Speed Issue

One of the greatest privileges offered by USB Type-C connector is the possibility to employ USB 3.1 interface with 10 Gb/sec bandwidth for data transfer means. However, speed via the interface may vary: USB 3.1 Gen 1 offers 5 Gb/sec, while Gen 2 offers 10 Gb/sec. Thus, actual data transfer speed relies not upon the connector, but upon the interface of the connected devices.

Energy Delivery Marvel

Type-C is able to deliver up to 100 W energy. This is quite enough for the charge-in of mobile gadgets as well as providing power supply to laptops, monitors, external HDDs, etc. Still, in order to enable the bus to deliver 100 W power, the device needs to support USB Power Delivery 2.0 (USB PD) specification. If it is absent, the bus will only provide 7.5 W (1.5A, 5 V) or 15 W (3A, 5 V), depending on the configuration.

Energy facilities of USB PD ports cannot be managed without power profiles. Profile 1 ensures up to 10 W delivery, Profile 2 – up to 18 W, profile 3 – up to 36 W, Profile 4 – up to 60 W, and Profile 5 – up to 100 W. Ports that correspond to the higher profile are thought to support all lower profiles. In addition, Type-C makes it possible to change energy delivery direction; hence, the consumer device can temporarily become the charger.

Alternative Options

From the outset USB Type-C has been developed as a comprehensive solution. As a result, apart from data transfer process it might be used in Alternate Mode for the realization of third-party interfaces.

For instance, VESA has already taken benefit from bus flexibility, by integrating video stream options due to DisplayPort Alt Mode. Having four super-speed pairs in disposition, it’s possible to allocate two of them for DisplayPort in order to receive imaging with 4K resolution. Yet, the other lines are distributed on USB needs. Furthermore, Type-C can be employed for audio streaming with the assistance of SBU1/SBU2 ports which are converted into AUX+/AUX- channels.