Patent EP-0178205-A1 (EP)
Inventor: LE HIR JEAN-PIERRE
IPC: H04L12/413
Filed: 1985-09-12
Abstract: 1. A digital network comprising first and second transmission conductor wires (2, 3) and several transmitting and receiving stations (11 , 1M-1 ) connected to said transmission wires, each station being capable of transmitting and receiving messages comprising serialised bits at least at a predetermined rate through the first transmission wire (2) and being identified by a respective address word, each message beginning with an address word identifying a target station for the message, the second transmission wire (3) being connected to all the stations (11 , 1M-1 ) and being in the first and second logic states (high "1" and low "0") when the first transmission wire (2) does not convey a message and is occupied by a message respectively, the transmitting and receiving stations (11 , 1M-1 ) being ordered as a function of respective priority words, each message transmitted by a station containing the priority word which is allocated to the station and precedes the address word in the message, and each transmitting and receiving station (11 , 1M-1 ) comprising state-changing means (6) so as to pass the second transmission wire (3) from the first state ("1") to the second state ("0") in response to a commande to transmit a message (DT) from the station and means (5, 7) for authorising the transmission of a complete message in the first transmission wire (2) after the second transmission wire (3) has passed from the first to the second state and on reception of the priority word of the station transmitted by said station through the first transmission wire (2), characterised in that said digital network is of the asynchronous type and the change from the first to the second state ("1" to "0") of the second transmission wire (3) is effected independently of the message bit rate by state-changing means (6) in the station and takes place at the end of a first predetermined period (epsilon) following a message transmission command (DT) from the station which depends only on the propagation time in the electronic components of the state-changing means (6), in that the state-changing means (6) in the station do not change the state of the second transmission wire (3) in response to a command to transmit a message (DT) from the station which takes place after the first predetermined period (epsilon) following a command for transmission from another station and when the second transmission wire (3) is in the second state ("0"), and in that after a second predetermined period (T0 ) following the change from the first to the second state ("1" to "0") of the second transmission wire (3) and independent of the message bit rate, the means for authorising transmission (5, 7) in the station transmit the serialised priority word from the station completely in the first transmission wire (2) then compare said transmitted priority word from the station (71T0 to 71T7 ) in its entirety and a priority word (71R0 to 71R7 ) received through the first transmission wire (2) following the transmission of said priority word by said station or the transmission of a priority word by at least one other station which almost simultaneously commanded the transmission of a message (DT) during said first predetermined period (epsilon), and finally authorise the transmission of a message by said station starting from an address word when said compared transmitted and received priority words (71T0 to 71T7 ; 71R0 to 71R7 ) are identical.