Encoding Modes
EXC (Extended Alphanumeric Compaction mode) - allows encoding of all printable ASCII characters into about 2 characters per codeword. Within the EXC mode there are several submodes:
Binary/ASCII Plus mode - allows encoding of 256 international characters including the full ASCII set plus any 8-bit value in the range 0 - 255. This mode allows encoding approximately 1.2 bytes per codeword and so is considerable less efficient than EXC mode.
Numeric mode - allows encoding of a string of digits with a density of approximately 2.95 digits per codeword. Recommended where more than 13 digits are to be encoded. Numeric mode symbols may not contain non-numeric characters.
The maximum capacity of PDF417 symbols is approximately as follows:
Numeric mode – maximum capacity 2700
digits*
Alphanumeric text – maximum capacity 1800 characters*
Byte values
– maximum capacity 1100 bytes
*Note that capital letters, punctuation, mode shifts and new lines/paragraphs reduce these value.
