9 INDUSTRIAL CONTROLLERS COMPRISING A DIGITAL COMPUTER FOR PERFORMING THE FUNCTIONS OF CONTROL LOGIC, RELAYS, TIMERS, COUNTERS, SEQUENCERS, CALCULATORS, SHIFT REGISTERS, AND STEPPING MOTOR CONTROLS; 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