Bar code processing system with multiport signal decoder

A digitizer/sequencer device (10) for the processing of scanner digital input data including bar code data is disclosed. The device is flexible and universal in nature in that it can provide inputs to both a fixed program decoder (20) for the decoding of the Universal Product Code (UPC) code as well as a programmable processor (26) which can decode UPC as well as a variety of many other bar codes. Further, the device can handle inputs from various types of scanners (11) include high-speed counter top, hand-held scanners and light pen scanners and magnetic card readers, which provide input data over a wide range of frequencies. A large number of individual frequencies are made available in the device. One of these frequencies may be optimally selected by the programmable processor (26) to provide an internal clock for the device and a clock frequency for the digitizer counters (S clock) and another of these frequencies may be selected to provide a clock frequency (M clock) for the hard wired decoder. A sequencing means (28) is used to control the operation of the device so that it steps through a predetermined number of steps after the occurrence of each transition in the incoming bar code data.