| 摘要 |
PURPOSE:To avoid a collision of signals transmitted from a remote side device and eliminate a time loss to ensure a quick start of communication, by waiting for a communication start command in the case of a transmission and a reception and then transmitting a communicating command in case no command is given within a certain time. CONSTITUTION:A connection is given to a communication sequence control circuit 1 connected to a communication circuit 16 by a changeover switch 2 performing a switch between an A-system circuit 3 and a B-system circuit 4. The modulators/ demodulators 5 and 10, code decoders 6 and 11 plus transmission control circuits 7 and 12 are provided to each of the circuits 3 and 4; and a common picture signal input/output circuit 14 is connected to the circuits 3 and In case a device of common system performs a transmission or a reception, a switching is given to the circuit 3 or 4 for the 1st and 2nd certain times to wait for a communication start command. Then a communication command is transmitted in case no command is given within a certain time to avoid a collision against the signal transmitted from a remote side device. Thus a quick start is made possible for a communication. |
