| 摘要 |
1509014 Data transmission SIEMENS AG 20 May 1975 [22 May 1974] 21384/75 Heading H4P Data terminal devices DEE are connected to a data network DN by way of respective devices DU and lines 103 to 114 carrying interface and control signals. Each device DU includes a device SW for the modified transmission of data signals, derived from its associated terminal device DEE, to the network DN over a line DS1 the arrangement being such that no continuous 0-states or continuous 1-states are applied to the network DN by this device SW; a device SRW for the reception and restoration into their original form of modified signals from other devices connected to the network DN; a switching device Ss0 which can bypass device SW to supply a continuous 0-state to the transmitting line DS1; a circuit Se0 serving to recognize any such continuous 0-state occurring on the receiving line DE1 and, upon recognition, to clear the connection in known manner over a device SD; a switching device Ssl which, when the terminal device DEE is not in a transmitting mode, supplies a continuous 1-state to the transmitting line DS 1 and which, when the device DEE is in a transmitting mode, causes the device SW to be switched on via a control input E/A; a circuit Sel responsive to the reception of a continuous 1-state; and a circuit t which delays the initiation of transmission of data from one terminal device to another for a time sufficient for the second device to become ready for operation. The specification describes how this arrangement enables semiduplex devices to be operated and controlled when connected to a data network possessing only fullduplex transmission paths. |
