Interfacing Optical Document Scanners:Principles and Practical Considerations
David J. Krus, Dennis Kodimer · Educational and Psychological Measurement · 1987
Handlers for interfacing the ScanTron 1400 and 2700 Optical Mark Readers with the IBM AT/XT/PC and Tandy 2000/1000/3000 iAPX 88/186/286 based computers were described. Differences between programming an RS232C serial port using BIOS interrupts and directly addressing the Motorola 8550 UART microprocessor were discussed together with general principles of decoding the data stream generated by a scanner.