A bar code reading system having a wand that detects variations in light reflected by bars and spaces of the label produces a sequence of corresponding pulses and intervals as the wand scans the label. The entire sequence of pulses and intervals is input to a microprocessor system which produces corresponding...http://www.google.com.au/patents/US4528443?utm_source=gb-gplus-sharePatent US4528443 - Bar code reading system and method
