A few years ago, you would plug in your mouse, keyboard, speakers, monitor, etc. into separate ports on a computer. Now, I have a dock that all my peripherals connect to, and my laptop is just connected to that dock through a single USB-C cable. There’s never any noticeable lag, either. What improvements have been made so that this is now possible?
In: Technology
USB data rates have increased with each version. USB 1 could go up to 12 Mbits/sec. USB 2 maxed out at 480 Mbits/sec. USB 3 can do 5Gbits/sec. USB 3.1 is up to 10 Gbit/sec. USB C connectors appeared with USB 3.
More bandwidth available means more connections into one port with no issues.
USB stands for Universal Serial Bus where Serial refers to data bits being sent one after the other, “in series” if you will. USB has incorporated improvements for each new version of the standard that allow for more data to be transferred by increasing the speed of bits. These include having more wires (to send data in each wire simultaneously), twisting the wires together to form “twisted pairs” that reduce noise, a layer of thin metal foil around the cable that “shields” from outside noise further, careful management of the distance between the metal core of each pole in the cable for reduced crosstalk between cables and many more. The reduction of noise is the barrier to having higher speed, because distinguishing between signal and noise becomes exponentially more difficult with higher bit rate. The circuit on each end of the cable has also improved organically with the introduction of gradually enhanced bus implementations such as PCI Express and the capability of pepherials such as fast SSD disks.
in general, about a decade ago, USB 3 hardware started coming out, allowing 5gbps of data transfer each way through a pair of twisted pairs instead of 480mbps unidrrectional over a single paid. (and this added 5 extra pins to the USB connector).
USB C adds a few extra pins and wires that can either be used for a second superspeed pair, or assigned for other purposes such as carrying video, and with hardware designed for it, that 5gbps limit was raised in some situations to 10gbps per lane (USB 3.x gen2) or higher for some alternative uses.
Original USB had 1 set of data pins and data was sent relatively slowly, although electricity itself moves fast the length of each pulse of data was quite long which limits how much can be sent in an amount of time. So it would be the equivalent of a dirt road with a speed limit of 10.
Over time the USB standard shortened the pulse of each signal which means more signals per second, which means faster speeds. So still a normal road with 1 lane in each direction but each version had a higher speed limit.
USB C added more data pins and further shortened the pulses, so now it’s like an interstate highway with 3 lanes in each direction and a speed limit of 100.
There were quite a few improvements, mostly having to deal with the ability with a chip to move that amount of data and still be cheap. However another issue was that in the past there was simply no need to move that much data on 1 cable. The original USB was a huge leap in not having to deal with a dozen different connectors, and nothing was moving much data. Today with storage being so fast there is a market to make USB faster to keep up.
To be clear one of the big improvements is optimizing the construction of the cable. As you increase the speed of a communication device, the signals start to get sloppier looking. By controlling the construction of the cable, you can move more and more data per second without it becoming unreadable.
Latest Answers