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INDUSTRIAL CONTROLLERS COMPRISING A DIGITAL COMPUTER FOR PERFORMING THE FUNCTIONS OF CONTROL LOGIC, RELAYS, TIMERS, COUNTERS, SEQUENCERS, CALCULATORS, SHIFT REGISTERS, DATA PROCESSING, STEPING MOTOR AND PRINTER CONTROL, AND OTHER NON-RELAY LOGIC FUNCTIONS; PROGRAMMING PANELS; TELEPHONE INTERFACES; COMPUTER INTERFACES, INTERFACE ADAPTER MODULES AND HOUSINGS; MONITOR PANELS; PROGRAM LOADERS; PRINTED CIRCUITS-NAMELY, REGISTER, SIGNAL CONDITIONING, OUTPUT, AND TELEPHONE COUPLER CIRCUITS; AND PARTS THEREFOR