Description

   Binary files cannot be transmitted directly as electronic mail;
   they must first be encoded into a "printable" format. This,
   of course, means that they must be decoded upon receipt. The
   ENCODING command is used to specify the encoding to be applied
   to files requested with the SEND command. When selecting an
   encoding, be sure to select an encoding which you can decode.
   If your mail is handled by PMDF, then you can decode any of the
   encodings offered by PMDF mail servers.

   The encoding specified with the ENCODING command applies to
   all subsequent SEND commands in the same message. It can be
   overridden with a subsequent ENCODING command or, on a per
   command, basis with the SEND command's /ENCODING qualifier. And,
   of course, encodings established in previous messages sent to
   the server have no effect on subsequent messages which you might
   send.

   The BASE64 and QUOTED_PRINTABLE encodings are described in RFC
   2045 (MIME, Part One). The HEXADECIMAL encoding is a simple
   hexadecimal encoding of the data. The data is encoded in 8 bit
   byte order. Each 8 bit byte is represented with two characters;
   the first character describes the high four bits and the second
   describes the low four bits. The UUENCODE encoding is compatible
   with the popular UUENCODE and UUDECODE utilities.

   BASE64 is usually the best encoding to use: it is most likely
   to survive any mangling that might occur as the mail message
   works its way through the networks to you (e.g., line wrapping,
   character set translation, space stripping, etc.).