160 and 32 are different ascii characters!
32 (0x20) is SPC - a normal, common or garden space.
160 (0xA0) is often a "non-breaking" space (one which wouldn't be the 'breaking point' of a line wrap). In other fonts it isn't - so sometimes you'll get the 'no chatacter to see here' back box. In SJIS, it is used as the start marker for one 'series' of two-byte characters.
SJIS is a form of Japanese encoding
based on JIS (ISO 2022) which uses a mix of single and double-byte sequences to represent normal ascii, and Japanese (or CJK: Chinese-Japanese-Korean) characters. Particular escape sequences define the transition between normal ascii and Japanese encoding.