What is USB C and USB TYPE C?

More and more mobile devices have USB-C sockets instead of the existing USB ports. This is designed to simplify the connection of mobile devices: Displays, chargers and headphones connect to the same jack, even at the same time as the dock.

All about a stripping: That's the idea behind USB Type C. For example, a PC monitor with type C input can be connected to notebooks and tablets with a single cable. It then runs USB and DisplayPort signals and in the opposite direction flows charging current for the battery.

The type C socket is not only more compact, but also more comfortable than the well-tried type a connector: At last it does not matter how the plug sits around in the socket. Many devices with type C sockets transmit data faster than before: via USB 3.1 SuperSpeedPlus, data flows twice as fast as via USB 3.0 (see table on page 108), on new MacBooks thanks to Thunderbolt 3 even faster.

But where there is light, there is also shadow: The full range of USB-C confuses potential users and the mix of incomplete specifications, poor documentation and low-cost products in the PC market makes you disappointment. Anyone who understands the ideas behind USB-C avoids making a purchase.

Functional mixture

When the new USB socket of type C was introduced, the reversible plug was first in the foreground. But USB-C can do much more, because the 24 contacts of the connector are flexible, depending on the device, cable or adapter. Thus, the new standard not only replaces previous type A and micro USB sockets, but also DisplayPort for external monitors, HDMI for TV sets, audio jacks for headphones - and also charging sockets to fill the batteries of mobile devices.

Unfortunately, not every device and each USB-C socket offers the same range of functions; Rather, it depends on the device, which functions are installed - and on which sockets. For example, there are notebooks with multiple type C sockets, some of which are suitable for charging or for connecting displays. Smartphones, in turn, often use their type-C jack only for charging, for data transmission in the high-speed mode of USB 2.0 - not with super speed - and as a replacement for a Jack Jack. USB c sockets from desktop PCs in the end, they often only supply power and data via super-speed or SuperSpeedPlus, but neither displayport signals nor higher charging capacities. Only HP shines with some mini-PCs, which, like some notebooks, have a single C cable to connect to suitable monitors, which then transmits USB data, DisplayPort signals and energy simultaneously (see p. 110). Actually, there are small logos - see infographic on the following page - that indicate the functionality of the respective Jack, but that does not use any manufacturer: only the manual remains.

Adapters and hubs

Older USB peripherals with type a connectors can be easily used on C-sockets, there are only a few euro electromechanical adapters: they only connect the contacts of a Type C connector with the USB 2.0, USB 3. x and power supply. Type a jack. Similarly-wired adapter cables also pair older USB hubs, hard drives or scanners with type B input jacks on Type C hosts.

Marking of USB Type C sockets

DisplayPort adapters for type C sockets are somewhat more complicated because they have to be chips: they sort the available signals and log on as adapters, so they communicate with the host. In this way, transmitted monitor signals use the "alt mode" of USB-C, which we explain from page 124. Additional Wandlerchips in the Alt-mode adapter convert DisplayPort to HDMI 1.4 or even HDMI 2.0 for 4k resolution. With the appropriate counterpart, i.e. a docking station, a Type C monitor or one of the hubs featured on the starting side 120, the image output will also work with USB data transfer and power supply to charge the batteries in the host device. In the simplest Minidocks or hubs, the USB-C socket is not used to connect additional USB-C peripherals, but purely as a charging port, the power of which you pass up.

USB-3.1 hubs, which actually transmit SuperSpeedPlus, cannot be bought at the moment: all previous ones create a maximum of super speed. Nevertheless, you may carry the term "USB 3.1", albeit with the addition Gen 1 (see table) - Here you have to be careful! There are, of course, only a few expensive storage media, which SuperSpeedPlus at all irritate (see p. 114); The super-fast copying of data works only if there is a very nimble mass storage in the host: A hard disk is far too slow, even a SATA 6G SSD is not enough, it must already be a NVMe SSD. This is true for Thunderbolt devices: Extreme transfer rates of more than 1 GByte/s are only useful for special purposes.

More power

Many notebooks and PCs with type C jacks provide higher performance to feed peripheral devices. USB 2.0 was only designed for 2.5 watts (5 volt/0.5 a), USB 3.0 already for 4.5 watts (0.9 a). USB C hosts can be designed for up to 7.5 or 15 watts (1.5/3 a), but 15 watts are not required; Already 7.5 watts suffice for USB-3.1 SSDs.

Basically new to USB-C is the ability to switch between the food and the consuming role in the power supply: for example, a C-socket is used for more tablets, smartphones and notebooks as a charging port. To fill the batteries of tablets and smartphones in an acceptable time, the above-mentioned performances of up to 15 watts suffice. For notebooks, however, you want more charging power, and that's exactly what USB power delivery is aiming for: USB PD uses the Qualcomm quick charge principle, known from smartphones. The power supply and the mobile device are higher voltages of 9, 12 or 20 volts and currents of a maximum of 5 a - i.e. up to 100 watts of power. Special Type C cables are also required for the highest performance.

In any case, USB PD is quite complicated and unfortunately only provides the theory for universal power supplies that feed any mobile device from the smartphone to the notebook. The practice looks different: some notebooks with type-C charging function can even be loaded with the supplied power supply.

Confusing abundance

USB-C is still quite new; There are currently many different implementations on the market: from the simple charging socket to the Thunderbolt 3, which even allows the connection of external PCIe graphics cards. Not all hosts, peripheral devices, hubs and power supplies cooperate with each other; Electronically marked cables for 5 A current can hardly be distinguished from unmarked outwards - and sellers of some cheap products suggest more functions than are actually usable. At present, it is well advised to select accessories very carefully and to pay attention to a right of return.