For 'U', I'd like to talk about the humble USB connector and how far it's come. In a distant era lost in the sands of time, known to us today only as the early 1990s, computer peripherals were connected with either D-Sub connectors or the PS/2 style keyboard/mouse connector. Then, in 1995, we saw the first Universal Serial Bus, or USB connector. It didn't have easily bent pins like a D-Sub or PS/2, took up less space, and could be connected quickly and easily. Those of us who first saw it, nearly two decades ago, thought that this was a nicer, more standardized way to connect keyboards, mice, and printers. It is that, of course, but also much more.
The neat thing about USB, as opposed to traditional serial inputs, is that it's addressable. This means that you can take one USB output on your computer, add a hub, and install an array of devices: printers, flash drives, keyboards, mice, IR emitters, or anything else you could imagine. A single USB controller can, in fact, operate 127 devices which can be arranged in various tiers or "levels". Each hub adds a level; one thing you might not know is that a 7 port USB hub is often really two four-port hubs stacked together. That means that four ports would be on a different level than the other three; if you're stacking an absurdly unrealistic number of USB devices, this is something you should know.
What else did USB do? Version 2.0 gave us the smaller mini and micro- connectors which fit onto smartphones, reducing the need for proprietary connectors. The fact that power is part of the USB standard means that, for the first time I can remember, we can have standard DC power for our various devices. In commercial installations, I see USB for data used all the time; often a client will have a system with more than one computer (usually a Windows machine and a Mac). At a remote location there can be one USB hub, taken to a switch via a USB over Cat5 extender. One could then switch a local port for a flash drive, a keyboard, a mouse, and even a webcam, interactive touchscreen, or other device between the two machines with the touch of a button. Now that we're up to USB 3 there's the possibility of very high-speed data transfer - enough for live audio or video. At around 4 gigabits per second it's not going to compete with HDMI or Displayport in sending very high-quality video, but it opens a whole new set of options.
Why is this interesting to me? Mainly because the creation of a simple, multipurpose interface for disk drives, printers, and input devices has turned into a major component of audio, video, and computer systems in ways we've not have guessed. It raises the next question: what are we just seeing today which will be an major part of our landscape tomorrow?