diff --git a/passcode.txt b/passcode.txt
new file mode 100644
index 0000000..990b6d3
--- /dev/null
+++ b/passcode.txt
@@ -0,0 +1,101 @@
+The following coding is used by the Icom software for encoding usernames and
+passwords in login packets. Columns are: ASCII decimal, character, encoded
+character. This listing is only valid for the first character. Subsequent
+characters are encoded to different values, and the algorithm is currently
+unknown.
+
+32  space 0x47
+33  !     0x5d
+34  "     0x4c
+35  #     0x42
+36  $     0x66
+37  %     0x20
+38  &     0x23
+39  '     0x46
+40  (     0x4e
+41  )     0x57
+42  *     0x45
+43  +     0x3d
+44  ,     0x67
+45  -     0x76
+46  .     0x60
+47  /     0x41
+48  0     0x62
+49  1     0x39
+50  2     0x59
+51  3     0x2d
+52  4     0x68
+53  5     0x7e
+54  6     0x7c
+55  7     0x65
+56  8     0x7d
+57  9     0x49
+58  :     0x29
+59  ;     0x72
+60  <     0x73
+61  =     0x78
+62  >     0x21
+63  ?     0x6e
+64  @     0x5a
+65  A     0x5e
+66  B     0x4a
+67  C     0x3e
+68  D     0x71
+69  E     0x2c
+70  F     0x2a
+71  G     0x54
+72  H     0x3c
+73  I     0x3a
+74  J     0x63
+75  K     0x4f
+76  L     0x43
+77  M     0x75
+78  N     0x27
+79  O     0x79
+80  P     0x5b
+81  Q     0x35
+82  R     0x70
+83  S     0x48
+84  T     0x6b
+85  U     0x56
+86  V     0x6f
+87  W     0x34
+88  X     0x32
+89  Y     0x6c
+90  Z     0x30
+91  [     0x61
+92  \     0x6d
+93  ]     0x7b
+94  ^     0x2f
+95  _     0x4b
+96  `     0x64
+97  a     0x38
+98  b     0x2b
+99  c     0x2e
+100 d     0x50
+101 e     0x40
+102 f     0x3f
+103 g     0x55
+104 h     0x33
+105 i     0x37
+106 j     0x25
+107 k     0x77
+108 l     0x24
+109 m     0x26
+110 n     0x74
+111 o     0x6a
+112 p     0x28
+113 q     0x53
+114 r     0x4d
+115 s     0x69
+116 t     0x22
+117 u     0x5c
+118 v     0x44
+119 w     0x31
+120 x     0x36
+121 y     0x58
+122 z     0x3b
+123 {     0x7a
+124 |     0x51
+125 }     0x5f
+126 ~     0x52