| 摘要 |
PURPOSE:To enable an opposite station to receive emergency data without any error in procedure of a sequence number, by discarding a frame being transmitted when the emergency data is generated and then setting a state before the transmission, and then transmitting the emergency data by using the discarded sequence number. CONSTITUTION:A central processor 1 sets the state variable of a frame to be sent out next in a register 8 under program control, and writes sequence numbers, etc., to be added to data in the register in a main storage device to add them as a part of transmitted data, and then the contents of the register 8 are transferred to a register 9 to update the contents of the register 8 into a next frame, thereby performing transmission from a circuit controller 2. If data to be transmitted in an emergency is generated after transmission indication is sent to the controller 2, a discard indication line 10 is turned on. The controller 2 sends a discard pattern to a circuit 11 to permit a receiving station side to discard it, and the processor 1 returns the stand-by contents of the register 9 to the register 8 to set a state before the transmission, thereby transmitting the emergency data by the sequence number of the discarded frame. |
