There is disclosed an input/output system, employed within a data processing system that includes a central processing unit (CPU). The CPU includes improved input/output shift register structure or apparatus for interfacing with an I/O bus (bus structure). The I/O structure includes improved CPU transceiver...http://www.google.fr/patents/US4047201?utm_source=gb-gplus-shareBrevet US4047201 - I/O Bus transceiver for a data processing system
