EMPTY-WORD CONTROL METHOD FOR PACING OF SERIES LINK AND OF SPEED OF DRIVER AND RECEIVER

PURPOSE: To provide a system which transfers information among the elements of a data processing complex by deciding the highest workable rates of a transmitter and a receiver to operate the transmitter at the decided rate, putting null words into the transmitter at its working rate, and then deleting the null words in a reception mode of the receiver. CONSTITUTION: The receiving hardware consists of a RECEIVER REG 1100 of 40-bit width, a NULL DETECT 1101 which checks the data used for a null word, and an ASYNC BUFFER 1102. The data on a RECEIVE DATA line 1103 are clocked by a RECEIVE CLOCK 1104 and inputted to the REG 1100. When the data show a null word, the load of the BUFFER 1102 is suppressed by an AND circuit 1109. The null word is needed when SYSTEM CLOCK 1105 has a speed lower than the CLOCK 1104.