Hi,
First time I saw these connectors was on the back of a
radio my mother
bought in Germany in 1960. :-)
This link will explain all:
http://en.wikipedia.org/wiki/DIN_connector
And then there's that "mini-" stuff that
seems so prevalent these days.
I hate those connectors with a passion, they're so small that they're almost
impossible to solder up. And half the time you spend so long trying to
solder to the pins that you end up melting the buggers....gah! :-(
TTFN - Pete.