JPH10327273A - Isdn basic interface station power feeding/power receiving circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a communication function which is not restricted to the basic call function of a terminal(TE) even in a situation where external power is not supplied by receiving the local power feeding current of reverse polarity, which is power-fed from an exchange, with a designated input resistance value. SOLUTION: A local power feeding/power receiving circuit 10 is connected in series to the line terminal equipment(NT) 30 connected to a U point interface and a power receiving part input resistance value setting part 12 sets an input series resistance value, and the power feeding current of the reverse polarity (inverse polarity: DC potential is higher in L2 line compared to an L1 line), which is power-fed from the exchange (LT) 20 with the input DC resistance value, is received. It is fed to the reverse reception part 31 of NT 30. A forward current bypass part 14 by-passes forward current. It is by-passed by an AC component/AC signal bypass part 15 and the AC component is prevented from flowing to a reverse power feeding/power receiving part 13. The input resistance value is automatically set in the power receiving part input resistance value setting part 12 based on a DC current value which is measured in the reverse current measuring part 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication line using a layer 1 protocol of an ISDN basic interface, which is connected in series to a line terminating device (hereinafter referred to as NT) connected to the U-point interface, and (Hereinafter referred to as LT) of the power supplied from the station, a surplus of the power supplied to the station caused by the difference between the maximum value of the power loss expected in the subscriber cable section and the actual power loss value different for each line. The present invention relates to an ISDN basic interface station power supply receiving circuit for receiving and effectively utilizing power.

[0002]

2. Description of the Related Art ISDN Basic Interface Layer 1
In a communication line adopting the protocol, the NT and its subordinate terminals (hereinafter, referred to as TE) can receive the station-supplied power from the LT. The LT performs normal power supply [+60 V (the L1 line is positive)] when the layer 1 is stopped, and reverse power [39 mA] in other states.
At the connection point of NT (approximately 28 V (the L2 line is positive)).

[0003] The station power that can be consumed in NT is ITU-
G of T. Up to 1W as described in Recommendation 961
The NT further supplies power to the TE from among them.

[0004] TEs that provide communication services to users are:
As described in the ITU-T Recommendation 1.430,
A maximum of 420 mW (40 V) of station power supplied from the NT can be used.

[0005] The value of 420 mW is determined by an international recommendation as a power value necessary for realizing a basic communication function in which TE is a minimum lifeline.
In order for the TE to provide more advanced communication services, it is necessary to supply an external power supply such as a commercial AC power supply.

[0006]

As described above, when external power cannot be supplied on a communication line using the layer 1 protocol of the current ISDN basic interface, TE has a capacity equivalent to the basic communication function. Only communication services can be realized.

[0007] The problem to be solved by the present invention is to enable the TE to realize an advanced communication function which is not limited to the basic call function and to provide it to the user even in a situation where external power cannot be supplied. .

[0008]

DISCLOSURE OF THE INVENTION ISDN according to the present invention
A basic interface station power receiving circuit (hereinafter simply referred to as a station power receiving circuit) is a station power receiving circuit connected in series to a line terminating device connected to the U point interface in a communication line using a layer 1 protocol of the ISDN basic interface. A power receiving circuit, comprising: an input resistance setting means for setting an input DC resistance value; and a reverse for receiving a station supply current having a reverse polarity supplied from an exchange with the input resistance value set by the input resistance setting means. Power supply and power receiving means,
It has.

In addition, there is provided a forward current bypass means which is connected in parallel with the reverse power supply / reception means and bypasses the normal polarity station power supply current so as not to flow to the reverse power supply / power reception means.

Further, there is provided an AC signal bypass means connected in parallel with the reverse power supply / reception means and bypassing to suppress a loss due to an AC signal component flowing into the reverse power supply / power reception means.

The input resistance setting means includes a reverse current measuring means connected in series with the reverse power feeding / receiving means for measuring a DC current value of reverse polarity, and a DC current value measured by the reverse current measuring means. Automatic input resistance value setting means for setting an input resistance value of the reverse power feeding / receiving means so as to be a value designated in advance.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIG.

In FIG. 1, reference numeral 10 denotes a station power receiving / receiving circuit according to the present invention, reference numeral 20 denotes an LT, reference numeral 30 denotes an NT, reference numeral 10 denotes a subscriber cable, and power supplied from the LT 20 is supplied to the NT 30 via the subscriber cable 10. The power is supplied to the reverse power receiving unit 31. The station power receiving circuit 10 includes a reverse current measuring unit 11, a power receiving unit input resistance value setting unit 12, a reverse power receiving and receiving unit 13, a forward current bypass unit 14, an AC signal bypass unit 15, an available surplus power calculation display unit 16 Having.

The reverse current measuring unit 11 detects NT3 in reverse power feeding (DC potential of line L2 is higher than line L1).
The DC current value supplied to 0 is measured. The DC resistance value is a small value that is almost negligible (specifically, a value of several Ω) as compared with that of NT30 (less than 1 kΩ).

The power receiving unit input resistance value setting unit 12 controls the input DC resistance value of the reverse power feeding power receiving unit 13 so that the current measurement value of the reverse current measuring unit 11 becomes a predetermined value (Imin). Set.

Regarding the value of Imin, the current value when the power supply to the LT is maximized (= 1 GTU of 1 TU-T).
961 Recommendation for current supply during reverse power supply (39 mA ± 1
0%), which is the minimum value of 35.1 mA), and a value obtained by adding a slight margin.

The reverse feed power receiving section 13 always receives the local power supply current from the LT 30 with the input DC resistance value of the value set by the power receiving section input resistance value setting section 12 (or more), and supplies the DC-DC converter The function supplies power to the NT 30 as a required DC voltage. This allows the LT20
Can always use power that is approximately equal to (or less than) the maximum station supply power that can be supplied.

The forward current bypass unit 14 is realized by a rectifier circuit such as a diode connected so as to allow current to flow only in the forward direction, and the forward current flows through the reverse power supply / reception unit 13 to increase the loop current. This prevents the layer 1 activation sequence from becoming abnormal. If the forward current bypass unit 14 is not provided, it is necessary to limit the impedance characteristics of the reverse power supply / receiver unit 13 (for example, a very small value must be taken for the forward current).

The AC signal bypass unit 15 has a U-point interface signal frequency (16
The impedance value with respect to 0 kHz) is realized by a large-capacitance capacitor having a direct (negligible if several μF or more) which can be ignored as compared with the signal input impedance (110Ω) of the NT30. Prevent deterioration.

The surplus power calculation display section 16 realizes a function of displaying the maximum value of surplus power that can be received by the present circuit to the user. Specifically, the maximum value of the surplus power is determined by the DC resistance value set by the power receiving unit input resistance value setting unit 12 and the current measurement value (1 min) by the reverse current measurement unit 11 after setting this resistance value. Should be calculated and displayed. It goes without saying that the means for displaying does not need to be particularly limited, but from the viewpoint of using the station-supplied power as effectively as possible, it is desirable to select one with low power consumption required for display.

According to the configuration shown in FIG. 1, in the communication line using the layer 1 protocol of the ISDN basic interface, the station power receiving circuit 10 according to the present invention is connected in series to the NT 30 connected to the U point interface. The input DC resistance value is set in the power receiving unit input resistance value setting unit 12, and LT2 is set using the set input DC resistance value.
Receiving a supply current of reverse polarity (reverse polarity: the L2 line has a higher DC potential than the L1 line) supplied from 0,
Power is supplied to the reverse power receiving unit 31 of the NT 30. And
The forward current is bypassed by the forward current bypass unit 14.

The AC component and AC signal bypass unit 15
Therefore, the AC component is prevented from flowing through the reverse power feeding power receiving unit 13.

Further, based on the DC current value measured by the reverse current measuring unit 11, the input resistance value is automatically set by the power receiving unit input resistance value setting unit (in this case, the automatic input resistance value setting means) 12. You.

FIG. 2 shows another embodiment of the present invention, in which power is supplied to a high-functional station power supply operation terminal (TE) 40. In FIG. 2, 32 is a T-point power supply unit, 41 is a T-point basic power reception unit, 42 is an additional power reception unit, RA, RB, TA, and TB are terminals (simultaneously representing a metallic cable).
R means reception, which performs signal transmission and power supply, and the other components are the same as those in FIG.

If the surplus power received by the reverse power supply receiving unit 13 is to be supplied to the TE 40 receiving the station supply current from the NT 30, a more advanced communication function that is not limited to the basic call function can be provided only by the station supply. Can be operated.

FIG. 3 shows still another embodiment of the present invention and shows power supply to a plurality of station power supply operation terminals.
That is, if the target to which the surplus power from the reverse power supply receiving unit 13 is supplied is another TE (not the TE 40 receiving the station supply current from the NT 30) 50, two units connected to the same line or It is also possible to operate a higher TE only with station power supply.

For power supply to the terminal, a dedicated cable may be used, or a bus wire under the NT (point T) may be used.

FIG. 4 is a diagram for explaining a method of increasing the available station power supply. The power to be effectively used in the circuit of the present invention is the difference between the DC resistance value of the subscriber cable section and the maximum allowable value. The power supply increases. Conversely, there may be cases where the DC resistance value is large and surplus power is not sufficient, but even in this case, if it is absolutely necessary to increase the available station supply power, multiple cables must be connected in parallel in the subscriber cable section. It can be realized by connecting and providing. That is, in FIG.
(A) shows the case where the number of the subscriber cables 100 is one, and (b) shows the case where the number of the subscriber cables 100 is two (two). Shown in the table.

In the circuit configuration described in the present embodiment, it is assumed that the power receiving unit input resistance value setting unit 12 automatically sets from the measured value of the reverse current value notified from the reverse current measuring unit 11 flowing through the line. However, if the DC resistance value of the line can be grasped in advance, it is possible to adopt a configuration in which the DC resistance value is manually set. In order to know the DC resistance value of a line, a user can use a variable resistor and a DC ammeter to determine the maximum DC resistance value that can secure a current value of 1 min. A method of calculating the DC resistance value from the following formula can be considered.

Further, a communication carrier that provides a line uses the circuit of the present invention to provide a communication circuit that provides a circuit having a small DC resistance value in a subscriber cable section for a special use requiring a station power supply operation. Services can also be implemented.

This circuit is not limited to the connection point on the NT side, and can be installed anywhere in the subscriber cable section between the LT and the NT. The examples are shown in FIGS.
It is shown in (c). Device of the present invention (station power receiving circuit 10)
5A can be installed on the user side in FIG. 5A, the installation location of the LT 20 in FIG. 5B, in the transmission path in FIG.

Each "part" in the above embodiment is
Corresponds to each "means" in the claims.

[0033]

FIG. 6 shows the effect of the present invention in comparison with the conventional example. FIG. 6A shows the case of the related art, and FIG. 6B shows the case of the present invention, showing the difference in available power. That is, in the present invention, the input (DC) resistance value (which is equal to the difference between the maximum value (referred to as LM) of the DC resistance of the subscriber cable section and the actual DC resistance value (referred to as LR) which differs for each line. By connecting the power receiving means having LD = LM−LR in series with NT, the power supplied to the station (LD × (39 mA ± 10%)) received therefrom can be used in TE.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a station power supply receiving circuit according to the present invention.

FIG. 2 is a block diagram showing another embodiment of the station power supply receiving circuit according to the present invention.

FIG. 3 is a block diagram showing still another embodiment of the station power supply receiving circuit according to the present invention.

FIG. 4 is a diagram illustrating a method of increasing available station power supply according to the present invention.

FIG. 5 is a diagram for explaining a variation of an installation place in the present invention.

FIG. 6 is a diagram for explaining an effect of the present invention.

[Explanation of symbols]

 Reference Signs List 10 power supply receiving circuit for station 11 reverse current measuring unit 12 input resistance setting unit for power receiving unit 13 reverse power receiving unit 14 forward current bypass unit 15 AC signal bypass unit 16 surplus power calculation display unit 20 LT 30 NT 40 TE 50 TE 100 Cable

Claims (4)

[Claims] 1. Layer 1 of ISDN basic interface
In a communication line using a protocol, a station power receiving circuit connected in series to a line terminating device connected to the U point interface, an input resistance value setting means for setting an input DC resistance value, and the input resistance value A reverse power supply receiving means for receiving a station supply current having a reverse polarity supplied from the exchange with the input resistance value set by the setting means.
SDN basic interface station power supply receiving circuit. 2. The power supply apparatus according to claim 1, further comprising a forward current bypass unit connected in parallel with said reverse power supply / reception means and bypassing said power supply means having a normal polarity so as not to flow to said reverse power supply / reception means. ISD described
N basic interface station power supply receiving circuit. 3. An AC signal bypass unit connected in parallel with the reverse power supply / reception unit and bypassing to suppress a loss caused by an AC signal component flowing into the reverse power supply / reception unit. Or the ISDN basic interface station power supply receiving circuit according to claim 2. 4. The input resistance setting means includes: a reverse current measuring means connected in series to the reverse power receiving / receiving means for measuring a DC current value of a reverse polarity; and a DC current value measured by the reverse current measuring means. 4. An automatic input resistance value setting means for setting an input resistance value of the reverse power supply / reception means so that a value of the reverse power supply / reception means becomes a predetermined value. ISDN basic interface station power supply receiving circuit.