Back from the old teletype days, there was a code set up for describing key strokes.
ASCII--- American standard code for information interchange.
Besides the regular letters and numbers, there are several other symbols that you can transmit...
Actually, it was the NEW teletype days. Teletype was about to become a waning technology by the time ASCII was introduced. (Not many folks in datacomm today were also working in datacomm when ASCII was adopted. I guess I establish my old phart credentials by pleading guilty to that.)
But the degree sign was not part of the ASCII code set. It was in the IA5, the international alphabet for data communications, which had room for twice as many characters as ASCII did.
I can review the gory history if anybody cares. But I hope nobody does; it isn't really that interesting.
Cheers! DaveT
