An
ITU standard which defines a method for how to
encode 32k data on a
64k ISDN B-channel.
Used for instance with the
PIAFS wireless data protocol. The
encoding works by setting the lowest
nibble of a
byte to
F, making it
insignificant to the
receiver (whom must understand the
data to be
decoded using I.460). Consider the following
example:
BF AD DF 3F 1F 3F 3F 7F DF 0F 0F DF
Would come out as:
BAD 31337 D00D
After being
decoded as I.460 data.
However: please take note that if you
implement an i.460
receiver the bottommost
nibble of the
byte does not indicate the
sync position of the data! Things may be shifted from what you would expect. Take for example this simple example:
12 34
Encodes as:
1F 2F 3F 4F
It may also encode as:
2F 4F 6F 8F
...as the topmost
nibble may be
shifted by n-positions (in this case 1 position). To illustrate futher:
0001 1111 (1F) may encode as 0010 1111 (2F) as the topmost nibble is shifted one to the left.