Abstract: A microprocessor based mark-sense ballot card reading system has automatic mark detection threshold adjustment, automatic skew and card speed correction, and provision for simultaneous, accurate reading of both sides of a ballot card regardless of card input orientation. A multidispatch, miltipage real time control program is utilized to enable multiple event detection on each card side and asynchronous processing of such multiple events on a two-sided card. Positive document sensing and control are monitored by the microprocessor control system. A folded card path card transport mechanism with diverter stations operates under microprocessor control to determine card destination.