RFC 2152 UTF-7 May 1997 Character ASCII & Unicode Value (decimal) ' 39 ( 40 ) 41 , 44 - 45 . 46 / 47 : 58 ? 63 Set O (optional direct characters) consists of the following characters (note that "\" and "~" are omitted): Character ASCII & Unicode Value (decimal) ! 33 " 34 # 35 $ 36 % 37 & 38 * 42 ; 59 62 @ 64 [ 91 ] 93 ^ 94 _ 95 ' 96 { 123 | 124 } 125 Rationale. The characters "\" and "~" are omitted because they are often redefined in variants of ASCII. Set B (Modified Base 64) is the set of characters in the Base64 alphabet defined in RFC 2045, excluding the pad character "=" (decimal value 61). Goldsmith & Davis Informational