Dell Precision 3431 Service Manual page 12

Alternate Mode
USB Type-C is a new connector standard that is very small. It is about a third the size of an old USB Type-A plug. This is a single
connector standard that every device should be able to use. USB Type-C ports can support a variety of different protocols using
"alternate modes," which allows you to have adapters that can output HDMI, VGA, DisplayPort, or other types of connections from that
single USB port
USB Power Delivery
The USB PD specification is also closely intertwined with USB Type-C. Currently, smartphones, tablets, and other mobile devices often
use a USB connection to charge. A USB 2.0 connection provides up to 2.5 watts of power — that'll charge your phone, but that's about
it. A laptop might require up to 60 watts, for example. The USB Power Delivery specification ups this power delivery to 100 watts. It's bi-
directional, so a device can either send or receive power. And this power can be transferred at the same time the device is transmitting
data across the connection.
This could spell the end of all those proprietary laptop charging cables, with everything charging via a standard USB connection. You could
charge your laptop from one of those portable battery packs you charge your smartphones and other portable devices from today. You
could plug your laptop into an external display connected to a power cable, and that external display would charge your laptop as you used
it as an external display — all via the one little USB Type-C connection. To use this, the device and the cable have to support USB Power
Delivery. Just having a USB Type-C connection doesn't necessarily mean they do.
USB Type-C and USB 3.1
USB 3.1 is a new USB standard. USB 3's theoretical bandwidth is 5 Gbps, while USB 3.1's is 10 Gbps. That's double the bandwidth, as fast
as a first-generation Thunderbolt connector. USB Type-C isn't the same thing as USB 3.1. USB Type-C is just a connector shape, and the
underlying technology could just be USB 2 or USB 3.0. In fact, Nokia's N1 Android tablet uses a USB Type-C connector, but underneath
it's all USB 2.0 — not even USB 3.0. However, these technologies are closely related.
Thunderbolt over USB Type-C
Thunderbolt is a hardware interface that combines data, video, audio, and power in a single connection. Thunderbolt combines PCI
Express (PCIe) and DisplayPort (DP) into one serial signal, and additionally provides DC power, all in one cable. Thunderbolt 1 and
Thunderbolt 2 use the same connector as miniDP (DisplayPort) to connect to peripherals, while Thunderbolt 3 uses a USB Type-C
connector.
Figure 4. Thunderbolt 1 and Thunderbolt 3
1. Thunderbolt 1 and Thunderbolt 2 (using a miniDP connector)
2. Thunderbolt 3 (using a USB Type-C connector)
Thunderbolt 3 over USB Type-C
Thunderbolt 3 brings Thunderbolt to USB Type-C at speeds up to 40 Gbps, creating one compact port that does it all - delivering the
fastest, most versatile connection to any dock, display or data device like an external hard drive. Thunderbolt 3 uses a USB Type-C
connector/port to connect to supported peripherals.
1. Thunderbolt 3 uses USB Type-C connector and cables - It is compact and reversible
2. Thunderbolt 3 supports speed up to 40 Gbps
12 Technology and components