USB Versions
USB
versions refer to the overall standard and they define the maximum
speed of the connection, the maximum power and much more besides. They
theoretically could be applied to any shape of connector so long as the
computer and device are connected up correctly.
USB 1.1
Although
USB 1.0 is technically the first version of USB it never really made it
to market so USB 1.1 is the first standard we all used. It could
deliver data at 12Mbps and maximum current draw of 100mA.
USB 2.0
The
second version of USB arrived in April 2000 and it provided a massive
boost in maximum data throughput, up to 480Mbps. Power draw was also
increased to a maximum of 1.8A at 2.5V.
USB 3.0
USB
3.0 was a big change as it brought new connector types to allow for its
extra speed and power draw, with them often coloured blue to denote
their prowess. USB 3.0 can run at up to 5Gbps, delivering 5V at 1.8A. It
arrived in November 2008.
USB 3.1
The latest
and greatest version of USB was released in July 2013, though uptake is
still almost non-existent. It can deliver 10Gbps of throughput while up
to 2A can be drawn over 5V, and optionally either 5A over 12V (60W) or
20V (100W). This is the reason the new MacBook can be powered just by
its USB connection.
USB Type-A
Type-A
is the classic USB plug as we have long known it. The chunky
rectangular plug was the original design and it remains the standard
plug for use at the host end of the USB cable.
Now Type-A has
gone through a number of changes to accommodate different versions of
USB, with more pins added to allow for the faster speeds of USB 3.0 for
instance. However the fundamental design of the plug has remained the
same, with the new connections incorporated in such a way that all USB
Type-A plugs and sockets are compatible no matter which version of USB
they use.
It’s not always the case that whatever you plug in
will work, as the newer standards of USB also deliver more power, which
may be required by whatever device you’re plugging in, but for the most
part they’re completely interchangeable.
There are also some
variations of Type-A including Mini Type-A and Micro Type-A but these
were never widely adopted due to the complicating nature of having
different types of USB socket on host devices. They are now deprecated.
USB Type-B
Although
there are some uses for Type-A to Type-A USB cables, typically the
other end of a USB cable uses a Type-B connector. This denotes the
device attached at this end as being the client and because these types
of device can vary so much we see much more variation in plug/socket
types used.
The original type-B plug is the odd tall plug with
the sloping top corners that you typically find on printers. This was
extended for the USB 3.0 standard to include an extra bump for some new
connections.
The classic mini-USB and micro-USB are also
variations of Type-B, along with the clunky micro-USB 3.0, which uses a
normal micro-USB connection with an extra plug that carries more power
connections.
Variations on Type-B have been far more widely
adopted due to the sheer necessity of having smaller plugs at the client
device end. Indeed there are many devices that use entirely proprietary
shape Type-B USB sockets, such as many of the odd shape plugs used on
older mobile phones.
USB Type-C
This
brings us to Type-C. Where Type-A and Type-B have had to work within
the framework of being backwards compatible, Type-C is intended to
replace both and is designed to be small enough to not need any mini or
micro variants. The intention is that it will completely replace all
types of USB on both host and client devices.
What’s more its
headline feature is of course that it’s reversible. This means you no
longer have to get the plug the right way round - or even the cable the
right way round - but instead, like Apple’s Thunderbolt connection,
it’ll work whichever direction you try – no more USB superposition.
To
enable this Type-C cables will actually require circuitry to tell which
way round they are and route power and data in the right way, just like
on Apple's Thunderbolt connection. This is unlike all existing USB
standards which are just 'dumb' cables.
Type-C also builds on
the new USB 3.1 standard so to all intents and purposes will be the
connection type that brings in the new power and speed advantages of USB
3.1.
Type-C will still be backwards compatible with existing USB variants but will of course require adapters.
Concerns
have been raised about the physical design of Type-C as the connector
looks potentially fragile with its hollow plug and a delicate tab in the
socket. In contrast Thunderbolt uses a sturdy thick metal plug that is
far more resilient. We'll just have to wait and see how well Type-C
devices hold up to wear and tear.
All told, USB Type-C is
definitely a step in the right direction and we can't wait for more
devices to start adopting it. We'd prefer to have more than one on the
next Mac-book, though, please Apple.
