MICR Commands and Parsing
3255 4073–002 11–11
In this example, without an exception table entry, the firmware would not be
able to pick out the check serial number because it is not separated from the
rest of the account number:
txxxxxxxxxt ccccxxxxxxxxxxo
In this example, without an exception table entry, the firmware would not be
able to pick out the check serial number correctly, because it is imbedded
within the rest of the account number:
txxxxxxxxxt xxx-ccc-xxxxxxxxxxo
Loading the Exception Table
The exception table begins at word 20 in NVRAM. Each entry takes five words.
There is room for eight exceptions with a sumcheck written in the last word. An
application can load local exceptions into the printer using the write NVRAM
command:
0x1B 0x73 n1 n2 k
which writes the two byte word n1:n2 to word k in NVRAM.
Exception Table Entry Format
Each exception table entry consists of five words. The first two words contain
the first eight characters of the transit number by packing the low order nibble
of the numeric transit number characters. For Canadian checks, eliminate the
dash and store the eight numerics.
The next three words are used as six individual bytes to tell the firmware how
to interpret the MICR characters which fall to the right of the rightmost transit
symbol. Each of the six bytes is positional and consists of two parts: character
type and number.
