JP2553861Y2 - Sensor unit for telephone line - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention is configured to selectively connect a telephone and another electronic device such as a facsimile to a telephone line via a relay switch, and the relay switch is provided. Relates to a telephone line sensor unit provided in a network control unit driven by a signal processing circuit in the electronic device for processing a line current flowing through the telephone line and switching the telephone line to the telephone side or the electronic device side for connection. .

(Prior Art) With reference to FIG. 2, a description will be given of a telephone line sensor unit in a conventional network control unit (a network controller at the lowest layer in a telephone network, abbreviated as NCU).

Terminals 1 and 2 are connected to a central office exchange. Each of the relay switches 3 and 4 has one circuit and two contacts, and each movable contact 3a and 4a is a telephone line to the corresponding terminal 1 and 2.
Connected via 1, l2. Double relay switch 3,4
One of the individual contacts 3b, 4b is connected to the primary winding 5a of the line transformer 5 and the other individual contact 3c, 4c is connected to the primary winding 6a of the line transformer 6 via the capacitor 7. And these individual contacts 3c, 4
c is also connected to terminals 10 and 11 on the telephone side. The line transformer 6 is provided to detect an AC signal included in a line current flowing through a telephone line, for example, an AC signal of 1100 Hz or the like which is a signal for operating a facsimile (hereinafter, referred to as a facsimile operation signal). Is well known.

The secondary winding 5b of the line transformer 5 is connected to an electronic device such as a facsimile via a two-wire / four-wire conversion circuit 8, and is connected to the secondary winding of the line transformer 6.
6b is connected to the signal processing circuit 9 in the facsimile. The two-wire / four-wire conversion circuit 8 converts the two-line telephone line on the secondary winding 5b side of the line transformer 5 connected to the input portion thereof into
The output unit converts the data into four lines. The signal processing circuit 9 determines whether the line current is on the telephone side or the facsimile side based on the presence or absence of the facsimile operation signal in the line current flowing through the telephone lines 1 and 12 and does not include the facsimile operation signal. When it is determined that the terminal is the telephone side, the movable contacts 3a and 4a of the relay switches 3 and 4 are connected to the individual contacts 3c and 4c, and the relay is determined when the terminal is determined to be the facsimile side by including the facsimile operation signal. The movable contacts 3a, 4a of the switches 3, 4 are switched so as to be connected to the individual contacts 3b, 4b. The telephone line sensor unit 12 in such a network control unit is inserted into one telephone line l2. The telephone line sensor unit 12 includes a photocoupler 13 including a light emitting element 13a that emits light when a line current flows in the direction of arrow a, and a light receiving element 13b that receives light emitted from the light emitting element 13a. It comprises a light emitting element 14a that emits light when a current flows, and a photocoupler 14 that includes a light receiving element 14b that receives light emitted from the light emitting element 14a.

Outputs of the light receiving elements 13b and 14b are output to terminals 15 and 16, respectively. A signal processing circuit 9 is connected to the terminals 15 and 16 via a detection circuit (not shown) for detecting the on / off state of the hook switch of the telephone. When turned off, the line current flows in the direction of arrow a, causing the light emitting element 13a to emit light. The light emission is received by the light receiving element 13b.
Output to the detection circuit via 5. Further, when the line current flows in the direction of arrow b, the light emitting element 14a emits light, and the emitted light is received by the light receiving element 14b, and the received light output is output to the detection circuit via the terminal 16. The detection circuit supplies the output provided from both terminals 15 and 16 to the signal processing circuit 9.

(Problem to be Solved by the Invention) In a network control unit including such a telephone line sensor unit 12, relay switches 3 and 4, line transformers 5 and 6, and photocouplers 13 and 14 are mounted on a mounting board. However, since all of them are large electronic components and have a large number of components, a large mounting space is required for the deployment, and the size of the board increases, and the network control unit is In addition to being a factor that hinders miniaturization, and being inferior in reliability because photocouplers 13 and 14 cannot detect line current with such high accuracy,
There is a disadvantage that the price of the network control unit is high due to the large number of parts used as a whole.

The present invention requires only one line transformer,
In addition, the line current and the AC signal (facsimile operation signal) included in the line current can also be detected magnetically, thereby reducing the number of parts used in the line transformer, which is a large-sized electronic component, and various electronic components. To reduce the size of the board on which the device is mounted and deployed, thereby facilitating the miniaturization of electronic equipment such as facsimile, improving the reliability by detecting line current with high accuracy, and improving the overall The purpose of the present invention is to reduce the number of used parts and lower the price of electronic devices.

(Means for Solving the Problems) A telephone line sensor unit according to claim (1) of the present invention selectively connects a telephone and another electronic device such as a facsimile to a telephone line via a relay switch. And the relay switch is provided in a network control unit that is driven by a signal processing circuit in the electronic device to switch and connect a telephone line to a telephone side or an electronic device side,
A detection coil for magnetically detecting a line current flowing through the telephone line, a polarity of the line current, and an AC signal such as a facsimile operation signal included in the line current; and a circuit current from the magnetism induced in the detection coil. A magnetic sensor that outputs a detection output after detecting an AC signal, an amplifier that amplifies the output from the magnetic sensor, compares the output from the amplifier with a corresponding reference value, and processes the comparison result in the signal processing. A comparator that outputs to the circuit; and a terminal that outputs, to the signal processing circuit, an output from the amplifier branched at a stage preceding the comparator.

In the telephone line sensor unit according to claim (2), the output from the magnetic sensor amplified by the amplifier different from the amplifier is supplied to the terminal.

(Operation) The detection coil is used to detect the line current and its polarity in the telephone line,
In addition, the magnetic sensor detects magnetism of an AC signal such as a facsimile operation signal included in the line current, and the magnetic sensor outputs an output corresponding to the line current and the AC signal to the amplifier from the magnetism induced in the detection coil. The amplifier amplifies the output of the magnetic sensor and provides it to the comparator.

The comparator compares the first output of the amplifier corresponding to the line current of one polarity and the second output of the amplifier corresponding to the line current of the other polarity with corresponding reference values. A comparison result with respect to the reference value of each output is output.

On the other hand, the output from the amplifier branched in the preceding stage of the comparator is given to the terminal, and according to the determination of the signal processing circuit based on whether or not the output from this amplifier is an output having an amplitude. The switching of the relay switch is performed. That is, at this time, if the output given to the signal processing circuit via the terminal has an amplitude, the relay switch is switched to the electronic device side, and if not, the relay switch is switched to the telephone side. It can be switched.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a circuit diagram of a telephone line sensor unit according to an embodiment of the present invention, in which parts and components corresponding to those of FIG. The description of the parts and components is omitted here.

In the present embodiment, a sensor unit 17 for magnetically detecting a line current is used instead of the sensor unit 12 including a photocoupler of the conventional example, and the line transformer 6 is omitted by using the sensor unit 17. The feature is that it is made possible.

That is, the sensor unit 17 is a detection coil 18 that is inserted into the telephone line l2 and magnetically detects the presence or absence of a facsimile operation signal in the line current, together with the line current and the polarity of the line current, and the detection coil 18 Hall element 19 as a magnetic sensor that detects a line current from the induced magnetism and outputs a different detection output according to its polarity, and an amplifier that amplifies the output from each output section 19a, 19b of this Hall element 19 And a differential amplifier 20. When a line current flows in the direction of arrow a (one polarity) due to the turning off of the hook switch, the Hall element 19 outputs the differential amplifier 20 via the output unit 19a.
When the line current flows in the direction of the arrow b (the other polarity), a negative output is output to the differential amplifier 20 via the output unit 19b.

At this time, if a facsimile operation signal is included in the line current, the Hall element 19 also outputs a detection output based on magnetism corresponding to the facsimile operation signal to the differential amplifier 20.

The sensor unit 17 also outputs the positive output (output corresponding to the line current of one polarity) and the negative output (output corresponding to the line current of the other polarity) of the differential amplifier 20 to the corresponding reference values V1, -V1 and a comparator 21 for outputting the result of the magnitude comparison of the positive and negative outputs with respect to the reference value to the signal processing circuit 9 via terminals 15 and 16;
And a terminal 22 for outputting the output from the differential amplifier 20 branched in the preceding stage to the signal processing circuit 9.
Therefore, at the terminal 22, an output appears in consideration of the facsimile operation signal during the line current. In this case, the terminal 22 may be provided with an output amplified by a differential amplifier 23 different from the differential amplifier 20 as shown by a dotted line, instead of the output from the differential amplifier 20. Good.

In operation, the detection coil 18 magnetically detects a line current flowing through the telephone line l2, its polarity, and a facsimile operation signal included in the line current. The Hall element 19 outputs to the differential amplifier 20 an output corresponding to the line current and its polarity from the magnetism induced in the detection coil 18. The differential amplifier 20 amplifies the output of the Hall element 19 and provides it to the comparator 21. The comparator 21 outputs a positive output from the differential amplifier 20 corresponding to the line current of one polarity, and a negative output from the differential amplifier 20 corresponding to the line current of the other polarity, to the corresponding reference values V1, After comparing with -V1, the result of magnitude comparison with respect to the reference value of each of the positive and negative outputs is output to terminals 15 and 16. On the other hand, the output of the differential amplifier 20 is branched at a stage preceding the comparator 21 and is supplied to the signal processing circuit 9 via the terminal 22. Therefore, the signal processing circuit 9 determines whether the line current is on the telephone side or on the facsimile side based on the positive / negative output appearing at the terminal 22, that is, whether the output has an amplitude. I do. That is, at this time, if the facsimile operation signal, which is an AC signal, is included in the initial line current, an output having an amplitude caused by the facsimile operation signal is supplied to the terminal 22.
If the output has an amplitude, the signal processing circuit 9 determines that the output is the facsimile side, and switches the movable contacts 3a, 4a of the relay switches 3, 4 to the individual contacts 3b, 4b. If the output does not have any, the movable contact 3a,
4a is switched to the individual contacts 3c and 4c.

By the way, in this embodiment, the electronic device is a facsimile, but it goes without saying that an electronic device other than a facsimile may be used, and an operation corresponding to each electronic device other than the facsimile operation signal is applied to the AC signal. Signals and control signals will be included.

(Effects of the Invention) As described above, according to the present invention, the number of the line transformers, which are large-sized electronic components, is reduced, so that the size of the board on which the various electronic components are mounted and arranged on the electronic device side can be reduced. Because the line current is detected magnetically, it can be detected with high accuracy to improve reliability, and the price of electronic equipment can be reduced with a decrease in the number of parts used. It has an excellent effect.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a telephone line sensor unit according to an embodiment of the present invention, and FIG. 2 is a circuit diagram of a conventional telephone line sensor unit. 3,4 ... relay switch, 5 ... line transformer, 9 ...
... Signal processing circuit, 15,16,22 ... Terminal, 17 ... Sensor unit, 18 ... Detection coil, 19 ... Hall element (magnetic sensor), 20,23 ... Differential amplifier, 21 ... Comparator , 1, l2 ...
…telephone line.

Claims (2)

(57) [Scope of request for utility model registration] An electronic apparatus, such as a facsimile, is selectively connected to a telephone line via a relay switch via a relay switch, and the relay switch is driven by a signal processing circuit in the electronic apparatus. A telephone line sensor unit provided in a network control unit for switching and connecting a telephone line to a telephone side or an electronic device side, the line current flowing through the telephone line, the polarity of the line current, and the line current. A detection coil for magnetically detecting an AC signal included in the detection coil; a magnetic sensor for detecting the circuit current and the AC signal from the magnetism induced in the detection coil and outputting a detection output; and an output from the magnetic sensor. An amplifier for amplifying the signal, and comparing the output from the amplifier with a corresponding reference value, and comparing the comparison result with the signal processing circuit. And a terminal for outputting to the signal processing circuit an output from the amplifier branched at a stage preceding the comparator. unit. 2. The telephone line sensor unit according to claim 1, wherein an output from the magnetic sensor amplified by an amplifier different from the amplifier is supplied to the terminal.