Almost every USB connector I've seen so far looks like a robot. Is this design required, and if so, why?
Assuming it's not a joke question and you're speaking about those square holes, they're there to interlock with spring-loaded tabs on the other part of USB connector. They make it so that some force is required to pull out the connector and it doesn't fall out by itself.
Figure 1. Image source: Digi-Key.
- Obviously the robot needs four legs for V+, Data+, Data- and GND.
- There are square holes on both sides of the Type A plug. One set holds the insert in place. The other accepts the spring grips shown in Figure 1. If you insert a USB plug slowly into a receptacle you should be able to feel it get pulled in by the springs.
- The case is pressed out of sheet metal so it has to be folded and joined at some point. One or two dovetails make sure that the case won't split. The join line may be determined by the USB standard so that it gives a visual clue as to which way is up. (Normally we use the USB logo to determine this but the logo can only be used under licence. Also the join line won't wear away with use!)
Interestingly the connectors are quite expensive at €2.47 for one, dropping to €1.28 for 2,450. I would have expected about one tenth of that price given how long we've been making these and how many billions must have be manufactured by now.