Incidentally this is why I see no problem with phrases like 'PIN number', despite others apparently being very bothered by them. English does not use a macro preprocessor to expand acronyms.
Constructions like 'PIN number' and 'ATM machine' are just fine from a linguistic standpoint. Using them has class connotations, but that doesn't make them wrong.
Adding sounds to single-syllable words is also helpful to reduce ambiguity.