What does PN stand for anyway?
I assume FN is function... but how about PN? Punction?
Like so many things with keyboards, the origin is in the distant past of computing, and is often forgotten in the modern use.
Keyboards have had Function keys for the longest time. In modern use they are fairly generic but they were mostly application specific in the old days. PC keyboards had F1 through F12, but other systems had more (F24, etc.). "Fn" just refers to the scheme of calling them F with a number. 'N' = number
In addition to the dedicated, application-specific Fn keys, many systems had programmable function keys, PF1, PF2, PF3, etc. Those keys could be programmed to extended characters or combination keystrokes and they were used extensively in point of sale systems, banking systems, booking systems, and the like. They usually had the same numbering scheme.
So, "Fn" is an obvious shorthand for "Function", and "Pn" follows for "Programmable Function".
These modern boards seem to use "Pn" for programming even though they don't have any PFn keys.
