초록 ▼

In a simultaneous communication as in a POS system in which the same data including a multiplicity of data blocks is transmitted from a controller to a multiplicity of terminals all at once, the controller transmits all of the data blocks to the terminals without receiving any acknowledgement from e

In a simultaneous communication as in a POS system in which the same data including a multiplicity of data blocks is transmitted from a controller to a multiplicity of terminals all at once, the controller transmits all of the data blocks to the terminals without receiving any acknowledgement from each of the terminals in the course of data transmission. Each time the data block is received, the terminals hold information concerning the acknowledgement of the data block. After the termination of transmission of the whole of the data, the controller receives the acknowledgement information from each terminal into a management table. Based on the contents of the mangement table, the controller retransmits the data to a terminal(s) indicative of a negative acknowledgement in a similar manner to the above-mentioned data transmission or while taking acknowledgement for each data block.

대표청구항 ▼

A simultaneous communication method of transmitting data, inclusive of a plurality of data blocks, in a local network in which the frequency of occurrence of transmission error is low, from a controller to a plurality of terminals all at once, comprising the steps of: (a) transmitting the data block

A simultaneous communication method of transmitting data, inclusive of a plurality of data blocks, in a local network in which the frequency of occurrence of transmission error is low, from a controller to a plurality of terminals all at once, comprising the steps of: (a) transmitting the data blocks of said data in sequence from said controller simultaneously to all of said plurality of terminals; (b) holding in each of said terminals a respective acknowledgement response for each data block; and (c) successively sending a single acknowledgement response from each of said terminals to said controller only upon termination of transmission of all of the data blocks of said data, said single acknowledgement response from each terminal indicating whether any data block in the data received by said terminal is erroneous data; wherein said controller retransmits all of the data on the basis of the acknowledgement response received from said terminals at least to ones of said terminals indicating a need for data retransmission, and said terminals which receive said retransmission send an acknowledgement response after each retransmission of one data block.