Abstract: A transmitting section 7a outputs a transmission signal to the side of a transmission line 1. A first switching section Qa1 outputs the transmission signal to the transmission line 1. A second switching section Qa2 outputs the transmission signal from the transmission line 1. A receiving section 9a receives the transmission signal from the transmission line 1. A first detecting section 13a detects the transmission signal flowing through the first switching section Qa1. A second detecting section 19a detects the transmission signal flowing through the second switching section Qa2. When the transmission signal from the transmitting section 7a is not detected at both the first and second detecting sections 13a and 19a, a selecting section 15a selects the receiving section 9a and outputs a reception signal.

Abstract: There is provided a bidirectional transmission coil capable of miniaturizing a structure and carrying out reliable transmission of a data signal. A transmitting coil L1 generates a magnetic flux of a transmission signal by a high frequency signal applied thereto. A receiving coil L2 is arranged to be positioned concentrically with the transmitting coil L1, for inducing a reception signal by the magnetic flux from outside. A first cancel coil Lac is connected to the transmitting coil L1 in series so as to be led-out from a middle of the transmitting coil L and is led-in to the lead-out part. The first cancel coil Lac is arranged so as to sandwich the receiving coil L2 between the first cancel coil Lac and the transmitting coil L1, wherein the magnetic flux in a direction opposite to the magnetic flux from the transmitting coil L1 is generated in the receiving coil L2.

Abstract: There is provided a bidirectional transmission coil capable of miniaturizing a structure and carrying out reliable transmission of a data signal. A transmitting coil L1 generates a magnetic flux of a transmission signal by a high frequency signal applied thereto. A receiving coil L2 is arranged to be positioned concentrically with the transmitting coil L1, for inducing a reception signal by the magnetic flux from outside. A first cancel coil Lac is connected to the transmitting coil L1 in series so as to be led-out from a middle of the transmitting coil L and is led-in to the lead-out part. The first cancel coil Lac is arranged so as to sandwich the receiving coil L2 between the first cancel coil Lac and the transmitting coil L1, wherein the magnetic flux in a direction opposite to the magnetic flux from the transmitting coil L1 is generated in the receiving coil L2.

Abstract: A transmitting section 7a outputs a transmission signal to the side of a transmission line 1. A first switching section Qa1 outputs the transmission signal to the transmission line 1. A second switching section Qa2 outputs the transmission signal from the transmission line 1. A receiving section 9a receives the transmission signal from the transmission line 1. A first detecting section 13a detects the transmission signal flowing through the first switching section Qa1. A second detecting section 19a detects the transmission signal flowing through the second switching section Qa2. When the transmission signal from the transmitting section 7a is not detected at both the first and second detecting sections 13a and 19a, a selecting section 15a selects the receiving section 9a and outputs a reception signal.

Abstract: To easily judge a transmission signal outputted from an own electronic device. A transmission part 7 outputs a transmission signal to a transmission path 1 side. Switching parts Q1 and Q2 are connected between a constant voltage power source and the transmission path 1, to switch on/off of a signal supplied from the constant voltage power source, being the transmission signal from the transmission part 7, and output it to the transmission path 1. A reception part 9 receives the transmission signal from the transmission path 1. A detection part 13 is connected between the constant voltage power source and the switching parts Q1, Q2, to detect the transmission signal from the transmission part 7 flowing through the switching parts Q1 and Q2. A selection part 15 selects the reception part 9, when the transmission signal from the transmission part 7 is not detected by the detection part 13.

Abstract: To easily judge a transmission signal outputted from an own electronic device. A transmission part 7 outputs a transmission signal to a transmission path 1 side. Switching parts Q1 and Q2 are connected between a constant voltage power source and the transmission path 1, to switch on/off of a signal supplied from the constant voltage power source, being the transmission signal from the transmission part 7, and output it to the transmission path 1. A reception part 9 receives the transmission signal from the transmission path 1. A detection part 13 is connected between the constant voltage power source and the switching parts Q1, Q2, to detect the transmission signal from the transmission part 7 flowing through the switching parts Q1 and Q2. A selection part 15 selects the reception part 9, when the transmission signal from the transmission part 7 is not detected by the detection part 13.