Comment by lifthrasiir

It originates from the code page 37, which is the EBCDIC-based character set for US and Canada. At least initially EBCDIC code pages are numbered sequentially while PC DOS code pages were numbered more or less randomly; I have no clue why it is the code page 437 and not 337. (I can see why it is not 137 nor 237, as later code pages were numbered from 251.)