Graphical symbols have been used for decades to label knobs, buttons, switches, and of course connectors. This is not just a computer phenomenon. I first became aware of product related symbols on my Dad's 1969 Volkswagen Beetle. I'm sure Volkswagen decided to use symbols for the same reason we do. Symbols are a very cost effective alternative to traditional language. It's much more expensive to create country unique models with translated nomencalture. The ISO has been the governing body for such matters for as long as I can remember. ISO is an acronym for the International Standards Organization. They have standards for almost anything imaginable, including symbols. Designers are certainly not strangers to the world of symbols. I would guess that nearly every designer has been pressed into service during their career to design a symbol or two. I've certainly designed my share. The one I designed that has achieved the most notoriety is clearly the symbol for ethernet. This appears on pretty much every personal computer in the world to label the ethernet port. I never imagined it would achieve this level of fame when I worked on this back in 1989 with my old IBM collegues Lou Behrens and Win Miller. It was first used on a link protocol converter, if you know what that is.
Symbols for local area network connections
The ethernet symbol was designed as part of a set that depicted all possible local area network connections available at the time. The design of the set is based on a common array of blocks to represent computers/terminals. The method by which they are connected is the only variable. The arrangement of the blocks is non-hierarchical to reinforce that no block is a controller of the local area network symbolized. That sounds so impressive, but it's right out of the old IBM Technical Disclosure bulletin where they were first published. Volume 32, Number 7 , December 1989, to be exact. You can file this one in your computer trivia file right beside the origins of the "Ctrl-Alt- Delete" key combination. Here's a test for you, anyone know who invented that?