OPW M00-051.00 FSC3000, Command-Line Configuration Manual

Page: 172 / 181

Checksums
The
checksum
is a number included with data to ensure the integrity of the data.
The checksum used by the FSC3000
™
is a 2-digit number calculated by adding the decimal values of the
ASCII characters in a string and truncating the sum.
For example, in the string ‘
/ABC
’, the decimal values for each character are: ‘/’ = 47, ‘A’ = 65, ‘B’ = 66 and ‘C’
= 67. Adding these numbers produces 245. Truncating the number in this case means removing all but the
last two digits – for 245, resulting in 45.
The checksum is included with transaction, card and account records sent by theFSC3000
™
. Checksum can
also be used on each record when using the ‘
RESTORE
’ command. As an example, the following
transaction record has a checksum of 08.
123/I/123089/1130/000001234/08|CR|LF|
IMPORTANT:
When calculating the checksum for a record, the slashes (‘/’) must be included
in the calculation.
EXAMPLE:
An example of a checksum in a ‘ RESTORE ’ command is:
RESTORE STATION12345/beatify/75|CR|LF|
The checksum is 75. Note that the slash and the blank space (between ‘ RESTORE ’ and
‘ STATION12345 ’ in the example above) must be included in the checksum calculation.
Doc. No.: M00-051.00 Rev.: 10
Page 172 of 181