| 摘要 |
PURPOSE:To simplify a circuit, and to reduce its cost by adding aNULL code sending-out instruction to one of instructions to be executed by a central control unit, and giving the NULL code sending-out instruction concerned to a prescribed circuit in an electronic exchange. CONSTITUTION:Before control information is sent out of a transmitting memory (SSM)12, a CC11 sends a NULL code sending-out command to a gate circuit 25 and a gate circuit 26 through an interface circuit (INF)19. In the course of receiving the NULL code sending-out command sent out of the interface circuit 19, and an overflow detecting signal from an overflow detecting circuit 23, the gate circuit 25 provided on a mixing circuit (MIX)15-3 sends a '0' pattern sending-out instructing signal to a data overflow circuit 24, and sends out a '0' pattern onto a circuit. In order to send out a '0' pattern of a prescribed bit length, the interface circuit 19 sends out a signal to the gate circuit 25 and the gate circuit 26 for a prescribed time, when the NULL code sending- out command from the CC11 is received. |
