I thought this was interesting as I myself have used these bar code scanners here doing data entry for Barack! They greatly speed up the process and our data entry is now finished daily instead of dragging out after big weekend canvassing. As the article indicates, all registered voters have been assigned a bar code (number) which is printed right on the canvassing list. Entry of each person is a swipe on their number and a swipe on their answer.
http://www.jamaica-gleaner.com/gleaner/20081013/int/int4.html