US 4,227,178 AGranted

Decentralized data transmission system

AssigneeInternational Business Machines Corporation

InventorsClaude J. Gergaud, Etienne Grimanelli, Andre G. Tracol

Life of this patent

Estimating the term…

Loading patent…

Abstract

Described is a decentralized data transmission system and a method of operating the system. A relatively high speed transmission medium connects a number of relatively lower speed terminals in a loop or similar configuration. A central or monitoring station is connected in the transmission medium which includes a memory table containing the listing of the station addresses connected to the transmission loop. The monitoring station operates as a control station for transmitting the address of a first station to be enabled to transmit a message. The addressed station recognizes its address and responds either with a message destined for another station or with a signal that no message is to be sent. At the end of a message, an enabled station sends a special character to notify the monitoring station that the next station in the memory table can be addressed to grant usage of the transmission medium.

Claims13

Dependent claims

In a data transmission system including a transmission medium to which are connected a plurality of transmitting stations and a monitoring station, a method of operating said system so that any information signals transmitted by a station will be received by all the transmitting stations and the monitoring station, said method comprising steps of:

transmitting from said monitoring station the address of a first transmitting station on said transmission medium;
receiving and recognizing said address at said first transmitting station and, responsive to said reception and recognition of said address, transmitting from said first transmitting station either a message or a status idle character when there is no data message for transmission, said transmitting of a data message being destined for one of said other transmitting stations and said data message beginning with the address of said destination transmitting station and ending with an end of message character;
and
receiving and recognizing either said status idle character or said end of message character at said monitoring station and, responsive to the reception and recognition of either of said characters, transmitting the address of a second transmitting station on said transmission medium.

1 more element

Dependencies are inferred from the claim text.