>>Whats an LRC?
>
>Hi Kevin,
>
>I was curious too, so I did a little research. This is what I found from:
>http://www.dict.org
>Just type or copy/paste "Longitudinal Redundancy Check" you will get the following:
>
>

>Longitudinal Redundancy Check
>
>           (LRC, Block Redundancy Check) An
>          error checking method that generates a longitudinal parity
>          byte from a specified string or block of bytes on a
>          longitudinal track.
>
>          The longitudinal parity byte is created by placing individual
>          bytes of a string in a two-dimensional array and performing
>          a Vertical Redundancy Check vertically and horizontally on
>          the array, creating an extra byte.  This is an improvement
>          over the VRC because it will catch an odd number of errors in
>          the individual characters of the string.
>
>

>

Yep, that's it.

It's used in RS-232 communications for extra secure applications where simple parity and flow control isn't enough to verify a transmission was received error free. You send a string of characters to a device along with the LRC and the receiver calculates it's own LRC to compare to the one received. Error occurs if they're different.

It's used by debit card pin entry device Verifone PINpad 1000se and I'm sure other devices.