JPH08280068A - Power supply adaptor for transmitter, and transmitter - Google Patents

Abstract

PURPOSE: To provide a power supply adaptor for a transmitter capable of supplying a power-supply power from a transmission line to each terminal concentrically. CONSTITUTION: An adaptor ADP is equipped with a power source part 21 for power supply provided with a constant voltage power source 26 and a backward current prevention diode 28, and a power source superposition delay circuit 22 which connects electrically the power source part 21 for power supply to the transmission line L1 after the power source of the power source part 21 for power supply is applied and prescribed delay time elapses, and also, it is equipped with a polarity detection circuit 23 which detects the polarity of the transmission line L1 and outputs a polarity detection signal, and a polarity switching circuit 25 which switches a connecting state between the power source superposition delay circuit 22 and the transmission line L1 by receiving the polarity detection signal from the polarity detection circuit 23 and outputs a power of polarity that coincides with the polarity of the transmission line L1 from the power source part 21 for power supply to the transmission line L1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply adapter for a transmission device and the transmission device. More specifically, the present invention relates to a power supply adapter of a transmission device and a transmission device capable of supplying power to a terminal of the transmission device in which a power supply voltage for polarity reference is superimposed on a transmission line.

[0002]

2. Description of the Related Art Conventionally, as a transmission device of this type, FIG.
There are the following. This transmission device is an inter-air-conditioner network system based on the HBS (Home Bus System) standard, and has four centralized control devices 6 as terminals.
1, 62, 63, 64 and six indoor units 65 as controlled devices are provided. The above four central control devices 61, 6
The 2, 63, 64 and the six indoor units 65 are connected to the transmission line 67.

The HBS standard specifies the transmission polarity.
That is, the connection polarity of the centralized control device with respect to the cables forming the transmission line 67 is designated.

Therefore, in this transmission device, a DC power supply voltage for polarity reference is superimposed on the transmission line 67, and the centralized control device 6
1 to 64 can detect the polarity of the cable (transmission line 67) by themselves so that the centralized control device can automatically connect to the transmission line with the specified polarity. As a result, so-called non-polarization can be achieved, and connection of the centralized control device to the cable (transmission line 67) is simplified.

By the way, in this transmission device, of the centralized control devices as terminals connected to the transmission line 67, only one unit (the centralized control device 61 in FIG. 6) set as the master device is for the polarity reference. A DC power supply voltage is supplied to the transmission line 67. The power source capacity of the DC power source is 16 V, 50 mA (maximum value). The power supply voltage and maximum supply current are values determined so that the connected centralized control device can accurately detect the polarity. In addition, in this transmission device, no matter how many centralized control devices are connected to the network, the centralized control device can be supplied with the power supply voltage for polarity reference to all the centralized control devices (terminals). All have a power source for the polarity reference.

FIG. 5 shows the configuration of the centralized control device 61 of this transmission device and the connection to the transmission line 67. As shown in FIG. 5, the centralized control device 61 includes a transmission / reception / protocol controller unit 71, a polarity detection unit 72, a transmission polarity switching unit 73, a power supply unit 75, and a power supply superposition unit 76.

The protocol controller section 71 outputs the control signal to the transmission line 67 from the terminals TxH and TxL to the transmitting section 85, while receiving the control signal from the transmission line 67 at the terminal RxD via the receiving section 83. . Further, the polarity detection unit 72 includes two photo couplers 72A and 72A.
Have B. The above two photo couplers 72A and 72
B is connected to the transmission line 67 in opposite polarities. Therefore, the polarity detection unit 72 can output a signal indicating the polarity of the transmission line 67 to the polarity detection terminals PT ₁ and PT ₂ of the protocol controller unit 71. Then, the protocol controller unit 71 receiving the polarity signal from the polarity detection unit 72 outputs a polarity switching signal from the polarity switching terminal KK to the polarity switching unit 73. The polarity switching unit 73, which has received the polarity switching signal, connects the transmission line 67 and the transmission unit 85 so that the control signals from the terminals TxH and TxL of the protocol controller unit 71 match the polarities of the transmission line 67. Switch the line connection.

On the other hand, the power supply section 75 is AC200 / 100.
Transformer 75A connected to V commercial power supply and this transformer 75
A diode bridge 75B connected to A and a smoothing capacitor 75 for smoothing the output from this bridge 75B
Equipped with C. Further, the power supply unit 75 has a terminal drive power supply unit 77 and a polarity reference power supply unit 78 connected to both ends of the smoothing capacitor 75C. The power supply unit 77 for driving the terminal supplies electric power for operating the centralized control device 61 itself.

The polarity reference power supply unit 78 supplies a polarity reference voltage to the transmission line via the power supply superposition unit 76. The power supply superimposing unit 76 includes the choke coil 70.
And a backflow prevention diode 81. The choke coil 80 is provided as an LPF (low-pass filter) and plays a role of blocking carriers of a transmission signal transmitted through the transmission line 67 from flowing into the power supply unit 75. The power supply superimposing unit 76 can output the reference voltage to the transmission line 67 only when the switch SW1 is turned on. Further, the polarity of the reference voltage from the power supply superimposing unit 76 to the transmission line 67 can be switched by switching the switch SW1.

[0010]

However, in the above-mentioned conventional transmission device, the central control device 61, which is set as the master unit, is equipped with the power source section 75 to another central control device 62, 63, 64. The power supply of the power source cannot be supplied.

Therefore, in this conventional example, power supply to each centralized control device is not performed via the transmission line 67. That is, as shown in FIGS. 5 and 6, each centralized control device 61, 62, 63, 64 is configured to independently perform power supply work at each installation location and receive power supply power from a commercial power supply. .

However, in order to obtain power supply power for driving a terminal (centralized control device) from a commercial power supply, a power supply circuit combining a switching regulator or a transformer and a stabilized power supply is required. This power supply circuit has a problem that it is large and expensive.

Further, since the AC commercial power source is not always installed in the immediate vicinity of the installation of the centralized control device, the centralized control devices 61, 62, 63, 64 are far from the AC power outlet or the power supply main line. In this case, there is a problem that the power line has to be laid around for a long time.

Further, the transmission line and the wiring for receiving power from the commercial power source may be wired in parallel at a short distance over a long distance, or the transmission line and the power wiring may be paired by using a multi-core cable. In this case, there is a problem in that noise of the power supply wiring is superimposed on the transmission line, which adversely affects signal transmission.

Therefore, an object of the present invention is to provide a power supply adapter for a transmission device and a transmission device capable of centrally supplying power supply power to each terminal from a transmission line.

[0016]

In order to achieve the above object, the transmission device according to the invention of claim 1 comprises a constant voltage power source and a backflow prevention diode for preventing current from the constant voltage power source from flowing backward. The power supply unit has a power supply unit, and the power supply unit is connected between the power supply unit and the transmission line, and the power supply unit waits for a predetermined delay time after the power supply unit for power supply is turned on. A power supply superimposing delay circuit for connecting the power supply section for conduction to the transmission line, and a polarity detection circuit connected to an input / output terminal connected to the transmission line, for detecting the polarity of the transmission line and outputting a polarity detection signal. Is connected between the power-supply superimposing delay circuit and the transmission line, receives the polarity detection signal from the polarity detection circuit, and supplies a power having a polarity matching the polarity of the transmission line for supplying the power. From a source unit to be outputted to the transmission line, it is characterized by comprising a polarity switching circuit for switching a connection state between the power line delay circuit and the transmission line.

The transmission device of the invention of claim 2 is a transmission device in which a terminal and a controlled device controlled by the terminal are connected to a transmission line, and the transmission according to claim 1 A power supply adapter for the device is provided, and power for driving the terminal is supplied from the power supply adapter to the terminal connected to the transmission line via the transmission line. I am trying.

[0018]

According to the power supply adapter having the above structure, first,
When the power supply for the power supply is turned on, the power superimposing delay circuit connects the power supply for power supply to the transmission line after a predetermined delay time has elapsed since the power was turned on.

The following operation is executed during a predetermined delay time after the power is turned on. That is, the polarity detection circuit detects the polarity of the transmission line connected to the input / output terminal, outputs a polarity detection signal, and the polarity switching circuit receives the polarity detection signal. Then, the polarity switching circuit switches the connection state between the power supply superimposing delay circuit and the transmission line, and electric power having a polarity that matches the polarity of the transmission line is output from the power supply unit for power supply to the transmission line. It is possible to connect.

Therefore, according to the power supply adapter of the present invention, the power for driving each terminal can be supplied from the transmission line to each terminal. From this, the following effects can be directly derived. That is,
Since each terminal can eliminate the need for the stabilized power supply circuit for receiving the driving power from the commercial power supply, the terminal can be downsized and the cost can be reduced. Therefore, the cost of the entire transmission device can be reduced. Even if the terminal is installed in a place where power supply wiring work is difficult, driving power can be supplied from the power supply adapter to the terminal via the transmission line. Therefore, the degree of freedom in installing the terminal can be increased.
In other words, for terminals installed near the mains of the power supply, power should be directly received from the above mains, while for terminals installed in places where power supply construction is not possible, power supply construction is possible. The driving power may be received from the power supply adapter installed in 1. via the transmission line.

If the power supply capability of the power supply unit for power supply is increased to supply power to a plurality of terminals via the transmission line, the power supply to the terminals can be centralized. You can Therefore, the cost of the transmission device can be reduced.

Further, by installing the power supply adapter of the present invention near the terminal for supplying power, the voltage drop (loss) due to the DC resistance included in the transmission line can be reduced, It is possible to reduce power consumption and contribute to energy saving.

Regarding the voltage condition, the polarity reference power supply voltage and the terminal power supply DC voltage do not substantially coincide with each other. Therefore, the power supply adapter of the present invention detects the polarity of the power source for the polarity reference superimposed on the transmission line by the polarity detection circuit and the polarity switching circuit, and adjusts its own power source in accordance with the detected polarity. The polarities of are matched. Thereby, it is possible to prevent reactive current from flowing between the polarity reference power supply and the power supply power supply. The reactive current is a current that flows backward from a terminal device having a low power supply voltage.

Further, since the power supply unit for power supply has the backflow prevention diode, the power supply for supplying power to the power supply of the other terminal outputting the voltage for polarity reference on the transmission line. The power supply for use is connected in parallel to the transmission line. Therefore, if the polarity reference voltage is higher than the terminal power supply voltage, the power supply power of the terminal supplied from the transmission line will not supply enough power for the polarity reference power supply. Supply to.
On the other hand, when the polarity reference voltage is lower than the terminal power supply voltage, the power supply power supplies all of the power supplied from the transmission line to the terminal.

According to the transmission device of the present invention, the power supply adapter supplies power for driving the terminal to the terminal connected to the transmission line via the transmission line. can do.

[0026]

The present invention will be described in detail below with reference to the embodiments shown in the drawings.

FIG. 1 shows the configuration of an embodiment of the transmission apparatus of the present invention. The ADP shown in FIG. 1 is an embodiment of the power supply adapter of the present invention. This power supply adapter ADP is connected to the transmission line L1. Centralized control devices 1 and 2 as terminals are connected to the transmission line L1.
And 3 are connected, and further, the indoor unit R of the air conditioner as the controlled device is connected. The centralized control device 1 is configured to be directly powered by an AC commercial power source. In addition, the power supply adapter ADP of this embodiment
Is also configured to be powered directly from an AC commercial power source. The power supply adapter ADP has a capability of supplying drive power to the centralized control devices 2 and 3.

As shown in FIG. 3, the transmission line L1 is composed of lines L1a and L1b. The power supply adapter ADP has a power supply power supply unit 21, a power supply superimposing delay circuit 22, a polarity detection circuit 23, and a polarity switching circuit 2.
5 is provided. The power supply unit 21 for power supply has a constant voltage power supply 26, a choke coil 27 connected to an output terminal of the constant voltage power supply 26, and the choke coil 27.
And a backflow prevention diode 28 connected to.

Further, the power supply superimposing delay circuit 22 is connected between the power supply power supply section 21 and the polarity switching circuit 25. The delay circuit 22 includes a relay 30 connected in series with the backflow prevention diode 28 and a transistor 31 as a switching element connected between the relay 30 and the power supply unit 21. The circuit 22 has one end connected to the base of the transistor 31 and the other end connected to the transistor 3
1 and the capacitor 32 connected to the choke coil 27, one end connected to the base and the other end connected to the relay 30 and the backflow prevention diode 2
8 is connected to the resistor 33. In the delay circuit 22, when the amount of electricity supplied from the power supply unit 21 reaches a predetermined value, the transistor 31 becomes conductive,
The relay 30 is turned on.

The polarity detection circuit 23 is formed by combining two photocouplers (not shown),
Input terminals t ₁₀ and t ₂₀ are connected to the transmission input / output terminals T ₁ and T ₂ . The output terminal t ₃₀ is connected to the polarity switching circuit 25. The polarity detection circuit 23 receives the signal from the transmission line L1, detects the polarity of the transmission line 1 and outputs a polarity detection signal to the polarity switching circuit 25.

The polarity switching circuit 25 is connected between the input / output terminals T ₁ and T ₂ and the power supply superimposing delay circuit 22. The switching circuit 25, as shown in FIG. 3, two of the transmission lines L1a through the input-output terminal T _1, T _2, is connected to L1b, receiving a polarity detection signal from the detection circuit 23 Thus, the connection state of the power supply section 21 with respect to the two transmission lines L1a and L1b can be switched. This switching is performed so that the polarities of the transmission lines L1a and L1b and the polarities of the power supply unit 21 match. Such a polarity switching circuit 25 is
For example, it can be configured by a driver circuit having a relay and a delay circuit.

As described above, the power supply adapter ADP
Is composed of four parts, that is, a power supply 21 for power supply, a polarity detection circuit 23, a polarity switching circuit 25, and a power supply superposition delay circuit 22. These four parts can be configured on a hardware basis without using a microcomputer or the like. Also, it can be configured without using any special IC. Also, these four circuits themselves are very simple.

Next, FIG. 4 shows the configuration of the centralized control devices 2 and 3 as the terminals shown in FIG. This centralized control device includes a protocol controller unit 41, a power supply unit 42, a polarity detection unit 43, a transmission polarity switching unit 45, a transmission unit 46, and a reception unit 47. The receiving section 47 includes transmission input / output terminals T ₁₀ and T ₂₀ and R _X D of the protocol controller section 41.
It is connected between the terminals. In addition, the transmission unit 46
Is the T _X H terminal, T _X L of the protocol controller unit 41.
It is connected between the terminal and the transmission polarity switching unit 45. In addition, the polarity detection unit 43 includes the transmission input / output terminal T ₁₀ ,
It is connected between T ₂₀ and the polarity detection terminals PT ₁ and PT ₂ of the protocol controller unit 41. Further, the power supply section 42 is connected to the transmission input / output terminals T ₁₀ and T ₂₀ . The power supply unit 42 includes a diode bridge 42A, a choke coil 42B, a smoothing capacitor 42C, and a terminal driving power supply unit 42D. Further, the polarity detection unit 43 is
Two photo couplers 43A and 43B connected to the transmission input / output terminals T ₁₀ and T ₂₀ with polarities different from each other.
It has. These two photo couplers 43A and 43B
Depending on the polarity of the transmission line 1, only one of them conducts. Therefore, the polarity detection unit 43 outputs a signal to only _one of the polarity detection terminals PT ₁ or PT ₂ of the protocol controller unit 41, depending on the polarity of the transmission line L1. The transmission polarity switching unit 45 receives the signal at the polarity detection terminal PT ₁ or PT _{2 from} the polarity switching terminal K of the protocol controller unit 41.
Upon receiving the signal from K, the connection state is switched so that the control signal having the polarity matching the polarity of the transmission line L1 can be sent to the transmission line 1. The transmitting unit 46 is a T _X H for signal transmission of the protocol controller unit 41.
Terminal receives a signal from the T _X L terminal, transmitting the polarity switching section 4
A control signal is output to the transmission line L1 via the line 5. On the other hand, the receiver 47 receives the signal from the transmission line L1 and inputs the received signal to the signal receiving terminal R _X D of the protocol controller 41.

Next, the centralized control device 1 of the transmission device shown in FIG. 1 has the same configuration as that of the conventional centralized control device shown in FIG.

According to the power supply adapter ADP having the above configuration, when the power supply unit 21 for power supply is first turned on, the power superimposing delay circuit 22 causes the predetermined delay time to elapse after the power is turned on. After that, power supply unit 2 for power supply
1 is conducted to the transmission line L1. Without this delay circuit 22, there is a possibility that power for terminal supply may be output before the power polarity of the polarity reference power source on the transmission line is determined.

The following operation is executed during a predetermined delay time after the power is turned on. That is, the polarity detection circuit 23 detects the polarity of the transmission line L1 connected to the input / output terminals T ₁ and T ₂ and outputs the polarity detection signal S ₁ from the terminal t ₃₀ . Then, the polarity switching circuit 25 receives the polarity detection signal S ₁ . Then, the polarity switching circuit 2
Reference numeral 5 switches the connection state between the power supply superimposition delay circuit 22 and the transmission line L1 so that electric power having a polarity matching the polarity of the transmission line L1 is transmitted from the power supply power supply unit 21 to the transmission line L1.
Set to the connection state that can output to 1.

Therefore, according to the power supply adapter ADP of the above embodiment, as shown in FIG. 1, the transmission line L1
Drive power can be supplied to the centralized control devices 2 and 3 set in the slave unit from the. Therefore, this embodiment has the following effects. That is, the central control device 2
Since and 3 do not need to have a stabilized power supply circuit for receiving drive power from a commercial power supply, the centralized control devices 2 and 3 as terminals can be downsized and the cost can be reduced. Therefore, the cost of the entire transmission device can be reduced. Further, the larger the number of centralized control devices connected to the transmission line, the greater the cost reduction. Further, even if the centralized control devices 2 and 3 are installed in a place where power supply wiring work is difficult, driving power can be supplied to the terminal from the power supply adapter ADP via the transmission line L1. Therefore, the degree of freedom in installing the centralized control devices 2 and 3 as the terminals can be increased. In other words, for centralized control equipment installed near the power supply main line, it is possible to receive power directly from the power supply main line, and for centralized control equipment installed in places where power supply construction is not possible, Driving power can be received from the power supply adapter ADP installed at a place where construction can be performed via the transmission line L1.

Further, as in this embodiment, the adapter ADP
The power supply capacity of the power supply unit 21 for power supply of
If power is supplied to the plurality of centralized control devices 2 and 3 via the transmission line L1, the power supply to the centralized control devices can be centralized. Therefore, the cost of the transmission device can be reduced.

By installing the power supply adapter ADP near the centralized control devices 2 and 3 for supplying power, the voltage drop (loss) due to the DC resistance included in the transmission line L1 can be reduced. You can Therefore, it is possible to reduce power consumption and contribute to energy saving.

Further, according to the transmission device provided with the power supply adapter ADP, wiring work for supplying drive power to the centralized control device can be simplified, and at the same time, each centralized control device can be installed. Installation flexibility is also increased. Therefore, according to the above transmission device, it is possible to achieve both cost reduction and improvement in design flexibility of the transmission device as a whole.

Further, as in this embodiment, the transmission line L
Centralized control devices 2 and 3 that receive driving power from 1, a terminal drive power supply unit that receives driving power from an external commercial power source, and a centralized control device 1 that incorporates a polarity reference power supply circuit (however, reverse current blocking) It is possible to establish a transmission device that coexists with (for example, having a diode for use).

In the above embodiment, the power supply adapter A is used.
There were two central control devices to which the DP supplies driving power, but if the setting of the power supply capacity of the power supply adapter ADP is increased or decreased, the type and number of centralized control devices that can be supplied with power from the power supply adapter can be freely set. be able to.

In the above embodiment, the power supply adapter ADP is dedicated to power supply for supplying drive power to the centralized control devices 2 and 3 as slave units. However, the power supply shown in FIG. If the adapter ADP10 for use also has the function of the centralized control device 1 as the master unit shown in FIG.
A transmission device having the configuration shown in can be realized. The centralized control device 1 has the same configuration as the centralized control device 61 shown in FIG. Therefore, the power supply adapter ADP10
Is the power source 7 for polarity reference provided in the centralized control device 61.
8, power supply superimposing unit 70, and protocol controller unit 71
It is necessary to include the transmitting unit 85 and the receiving unit 83.

[0044]

As is apparent from the above, the power supply adapter of the transmission device of the present invention is for power supply having a constant voltage power source and a backflow prevention diode for preventing current from the constant voltage power source from flowing backward. The power supply unit, a power supply superposition delay circuit that connects the power supply power supply unit to the transmission line after a predetermined delay time has elapsed after the power supply power supply unit was turned on, and the polarity of the transmission line is detected and the polarity is detected. The polarity detection circuit that outputs the detection signal and the polarity detection signal from the polarity detection circuit are received to switch the connection state between the power supply superimposition delay circuit and the transmission line, and the polarity of the power supply power supply unit matches the polarity of the transmission line. And a polarity switching circuit for outputting the electric power of the polarity to the transmission line.

Therefore, the power supply adapter of the transmission apparatus of the present invention can supply the power for driving each terminal to each terminal from the transmission line. From this, the following effects can be directly derived. That is, since each terminal can eliminate the need for the stabilized power supply circuit for receiving the driving power from the commercial power supply, the terminal can be downsized and the cost can be reduced. Therefore, the cost of the entire transmission device can be reduced. Even if the terminal is installed in a place where power supply wiring work is difficult, driving power can be supplied from the power supply adapter to the terminal via the transmission line. Therefore, the degree of freedom in installing the terminal can be increased. In other words, for terminals installed near the mains of the power supply, power should be directly received from the above mains, while for terminals installed in places where power supply construction is not possible, power supply construction is possible. The driving power may be received from the power supply adapter installed in 1. via the transmission line.

Further, if the power supply capacity of the power supply unit for power supply is increased to supply power to a plurality of terminals via the transmission line, the power supply to the terminals can be centralized. You can Therefore, the cost of the transmission device can be further reduced.

Further, by installing the power supply adapter of the present invention near the terminal for supplying power, the voltage drop (loss) due to the DC resistance contained in the transmission line can be reduced. It is possible to reduce power consumption and contribute to energy saving.

According to the transmission device of the invention of claim 2, since the power supply adapter is provided, wiring work for supplying drive power to each terminal can be simplified. , The degree of freedom in installing each terminal will also increase. Therefore, according to the transmission device of the present invention, it is possible to achieve both cost reduction and improvement in design flexibility of the transmission device as a whole.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a transmission device of the present invention.

FIG. 2 is a diagram showing a modification of the embodiment of the transmission device.

FIG. 3 is a diagram showing a configuration of an embodiment of a power supply adapter of the present invention.

FIG. 4 is a diagram showing a configuration of centralized control devices 2 and 3 provided in the embodiment of the transmission device.

FIG. 5 is a diagram showing a configuration of a centralized control device included in the conventional transmission device.

FIG. 6 is a diagram showing a conventional transmission device.

[Explanation of symbols]

ADP ... power supply adapter 1, 2, 3 ... centralized control device,
R ... indoor units, L1 ... transmission line, L1a, L1b ... line, T _1, T ₂ ... transmission input and output terminal, 21 ... power supply for the power supply unit, 22 ... power line delay circuit, 23 ... polarity detection circuit, 2
5 ... Polarity switching circuit, 26 ... Constant voltage power supply, 27 ... Choke coil, 28 ... Reverse current prevention diode, 30 ... Relay,
31 ... Transistor, 41 ... Protocol controller section, 42 ... Power supply section, 43 ... Polarity detection section, 45 ... Transmission polarity switching section, 46 ... Transmission section, 47 ... Reception section.

Claims (2)

[Claims] 1. A power supply power supply unit having a constant voltage power supply and a backflow prevention diode for preventing reverse current flow from the constant voltage power supply, and between the power supply power supply unit and the transmission line. Connected to the transmission line, and a power supply superimposing delay circuit that connects the power supply power supply unit to the transmission line after a predetermined delay time has elapsed since the power supply power supply unit was turned on. Is connected to the input / output terminal, is connected between the polarity detection circuit that detects the polarity of the transmission line and outputs a polarity detection signal, and is connected between the power supply delay circuit and the transmission line. Upon receiving a polarity detection signal from the polarity detection circuit, the power superimposing delay circuit and the power supply superimposing delay circuit so that the power having the polarity matching the polarity of the transmission line is output from the power supply unit for power supply to the transmission line. A power supply adapter for a transmission device, comprising: a polarity switching circuit that switches a connection state with the transmission line. 2. A transmission device in which a terminal device and a controlled device controlled by the terminal device are connected to a transmission line, comprising the power supply adapter of the transmission device according to claim 1. A transmission device, wherein power for driving the terminal is supplied from a supply adapter to the terminal connected to the transmission line via the transmission line.