An Introduction to USB Technology

In 1996, The USB-IF, USB Integrator’s Forum, was formed. It consisted of 7 major computer companies at the time, IBM, Microsoft, Intel, NEC, Nortel, DEC and Compaq, who set off to create a standardized connection for peripheral devices (keyboards, mice, video cameras, printers, portable media players, disk drives, etc.) to connect to personal computers. The USB (Universal Serial Bus) specifications for cables and connectors they created became a universal standard by 2000 when USB 2.0 was released.

USB Images

There are (4) generations of the USB standard: USB 1.0, USB 2.0, USB 3.0, and USB 4.0.  All USB has 2 components: data rate (the speed that data travels over the cable) and charging power. USB 1.0, launched in 1996, with a second version in 1998, offered a minimal 12 Mbps (megabit per second) data rate and no power. USB 2.0, also called USB Hi-Speed, provided 480 Mbps (megabits per second) and 2.5 Watts of power. This is very slow data transfer and limited power.

In 2008, USB 3.0, referred to as SuperSpeed, was launched and the data transfer was increased over 10 times to 5 Gbps (1 Gb = 1000 megabits). And the charging power tripled to up to 7.5 Watts, which is a relatively good charging speed. USB 2.0 and 3.0 is differentiated by the color of the interior of the port and the plastic in the connector itself. USB 2.0 is always white in both. USB 3.0 is usually blue and sometimes black.

In 2014 USB 3.1, referred to as SuperSpeed+, was developed and it changed everything. First, the data transfer speed was doubled to up to 10 Gbps (3.1 Gen 1 provides 5 Gbps and 3.1 Gen 2 maxes out at 10 Gbps). But the real game changer was in the power, referred to as PD, Power Delivery. USB 3.1 provided up to 100W of power. The reason this made such an impact is because most notebooks require from 60W to 100W of power to charge and now USB can be used to charge a notebook (for example, from a USB docking station).

But the amazing aspect of the new technology was that USB 3.1 allowed the SAME cable to transfer data AND provide power. This means that one cable from a USB dock to a notebook could provide the data transfer from notebook to dock (and then off to the monitors) AND charge the notebook at the same time. This is a huge benefit in shared desking where any employee can grab a desk, plug the single upstream cable into their notebook and be fully connected to the monitor(s) while charging their notebooks, preventing the need to carry their notebook charging cable.

We often hear of the 3.1 technology being referred to as Type-C. This is because all USB 3.1 cables use Type-C connectors (but not all Type-C uses 3.1, for example, in new smartphones). The letter types are all just the physical connector, that is the end piece that plugs into the device.

Major connector types are shown below, all denoted by their letter designation, with the common Type-A on the far left and the new Type-C on the far right.

USB types

USB 4.0 specs were released in August 2019. They are based on the Thunderbolt 3 (a separate hardware interface developed by Intel) protocol specifications of 40 Gbps data rate (very fast) with the same USB 3.1 PD. The first USB4 compatible products were due for release in late 2020 but may be delayed.


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