Connected: An Internet Encyclopedia
4.2. The "Q" encoding
Up:
Connected: An Internet Encyclopedia
Up:
Requests For Comments
Up:
RFC 1522
Up:
4. Encodings
Prev: 4.1. The "B" encoding
Next: 5. Use of encoded-words in message headers
4.2. The "Q" encoding
4.2. The "Q" encoding
The "Q" encoding is similar to the "Quoted-Printable" content-
transfer-encoding defined in RFC 1521. It is designed to allow text
containing mostly ASCII characters to be decipherable on an ASCII
terminal without decoding.
- Any 8-bit value may be represented by a "=" followed by two
hexadecimal digits. For example, if the character set in use
were ISO-8859-1, the "=" character would thus be encoded as
"=3D", and a SPACE by "=20". (Upper case should be used for
hexadecimal digits "A" through "F".)
- The 8-bit hexadecimal value 20 (e.g., ISO-8859-1 SPACE) may be
represented as "_" (underscore, ASCII 95.). (This character may
not pass through some internetwork mail gateways, but its use
will greatly enhance readability of "Q" encoded data with mail
readers that do not support this encoding.) Note that the "_"
always represents hexadecimal 20, even if the SPACE character
occupies a different code position in the character set in use.
- 8-bit values which correspond to printable ASCII characters other
than "=", "?", "_" (underscore), and SPACE may be represented as
those characters. (But see section 5 for restrictions.)
Next: 5. Use of encoded-words in message headers
Connected: An Internet Encyclopedia
4.2. The "Q" encoding