text --> IA5 ?

> Content-type:  IA5
> Content-type: USASCII
> Content-type: NVT-ASCII
IA5 is a character set.  USASCII is a codeset.  I don't know what
NVT-ASCII is.  I would prefer if it refered to an ISO standard.  I
think IA5 is ISO 6429.  In any case I think we are trying to specify
the character set not the codeset.  This mail is being sent from an
EBCDIC system and is in IA5 but not in USACII (at least until it
leaves here :-).