Control system bidirectional interface

Claim 1

A control system for transferring items of information over data lines between remote terminals and a receiving device comprising: a first register in each said terminal for accumulating an item of information to be transferred to said receiving device; clock means including a clock pulse generator for producing transfer pulses occurring at a first rate, a synchronizing generator for producing synchronizing pulses at a lower rate, and mixer means, responsive to both generators for producing a recurring series of timing pulses including a synchronizing pulse and a number of transfer pulses; first driver means, responsive to said first register, for delivering said items to a said data line for transfer to said receiving device; a second register in each said terminal for accumulating an item of information received from said receiving device on a said data line; first gating means for enabling said first driver means to deliver an item of information from said first register to said receiving device over a said data line in response to a first group of said transfer pulses and for enabling said second register to receive an item of information from said receiving device over a said data line in response to a secOnd group of said transfer pulses; second driver means in said receiving device for delivering an item of information on a said data line to a said terminal; scanner means in said receiving device for receiving an item of information from each data line of each terminal in sequence; and second gating means, responsive to said first group of transfer pulses, for enabling said scanner means to receive items of information from a said terminal over a said data line and responsive to said second group of transfer pulses, for enabling said second driver means to deliver an item of information to a said terminal over a said data line.