JPS6333961A - Key telephone system - Google Patents

Abstract

PURPOSE:To contrive to attain the miniaturization for the entire set and low cost by providing a facsimile call signal supply circuit to a trunk line interface circuit and providing a facsimile connection control means to a central control circuit so as to simplify the trunk line interface circuit. CONSTITUTION:The trunk line interface circuit is provided with a facsimile call signal supply circuit A, which supplies a specific facsimile call signal coming from a trunk line side to a facsimile equipment via a main signal path of a facsimile terminal interface circuit. Further, a central control circuit is provided with a facsimile connection control means B, whichcontrols the trunk line interface circuit to close a DC loop of a trunk line with a specific facsimile call signal is detected by a facsimile equipment and it is informed from the facsimile terminal equipment interface circuit. Thus, a circuit to detect a specific facsimile call signal from the trunk line interface circuit is not required.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an improvement in a button telephone device to which a facsimile device can be connected.

(Prior Art) Conventionally, this keyaki button telephone device has been configured as follows, for example. Figure 3 shows its block configuration.
This device includes office line interface circuits (COU) 21 to 2n provided corresponding to a plurality of office lines 11 to 1n, respectively;
Terminal interface (STU) 41 to 4 m provided for each of multiple key telephones (EKT) 31 to 3 m
and a facsimile terminal interface circuit (FSTU) 5 for connecting a facsimile device (FAX) 50.
1, and each of these interface circuits 21 to 2n
, 41-4m, and 51 using a central control circuit (CCU>7
0, the crosspoint switch 60 selectively connects the key telephones 31 to 3m, between the key telephones 31 to 3m and each central office line 11 to 1n, and between the facsimile machine 50 and the central office line 11. . . . 1n, respectively. Note that 80 is a tone signal generation section that generates various tone signals for control, and 90 is a power supply section.

By the way, the station line interface circuit 2 of this conventional device
1 to 2rl and each terminal interface circuit 41 to 4m,
51 is configured as shown in FIG. 4, for example. Of these, the office line interface circuits 21 to 2n and the terminal interface circuits 41 to 4m have the same configuration, so only the office line interface circuit 21 and the terminal interface circuit 41 will be shown and explained in FIG. 4. First, the office line interface circuit 21 includes a 1681 detection circuit 214 and a 1300H2 detection circuit 217 as a calling signal detection circuit.
Of these, 130,082 detection circuits 217
is connected between the tip line T of the central office line 11 and the ring line 8 via a changeover switch 211. This changeover switch 21
1 operates according to instructions from the control circuit (CG) 210, and the 130 ON? The detection circuit 217 and the diode bridge circuit 2'13 are alternatively connected to the office line 11. 16 again
8! The detection circuit 214 includes a bypass circuit 212 for passing 16 Hz between the tip line T and the ring line 8 of the central office line 11.
and a diode bridge circuit 213, respectively, and are then connected via a changeover switch 216. This changeover switch 216 operates according to instructions from the control circuit 210 in the same manner as the changeover switch 211 described above, and connects the central office line 11 to the
6) Connecting the lx detection circuit 214 and the DC loop circuit 215 alternatively. Note that 218 is a transformer that connects the terminal interface circuit and the station ta11 during a call or communication.

On the other hand, the facsimile terminal interface circuit 51 is
The above office line interface circuit 21 and facsimile machine 5
transformer 511 and signal line 517 connecting between
It further includes a 16Hz generation circuit 513 and a DC current generation circuit 514. These 1682 generation circuit 513 and DC current generation circuit 514 are connected to a control circuit (C
C) It is selectively connected to the signal line 517 via a changeover switch 512 that operates according to an instruction from 510.

Note that 515 is a DC power supply that supplies line voltage of 48V to the facsimile machine 50, and 516 is a DC current detection circuit, which detects the DC current from the DC current generation circuit 514 to the facsimile machine 50. is supplied, this state is detected and the control circuit 51
Notify 0.

Also, a terminal interface circuit 41 for the button telephone 31
has an audio transformer 413 connected to the button telephone 31 via an audio signal 1411, and a data transformer 414 connected to the button telephone g431 via a control signal line 412. 413, an audio signal line is connected between the button telephone 31 and the crosspoint switch 60. Further, a data transformer 414 connects a control data line between the button telephone 50 and the central control circuit 70. still,
415 is an interface circuit for transmitting control data.

In such a configuration, for example, if the central office line 11 is connected to the subscriber telephone network and in this state a 16-Hz paging signal arrives from an exchange (not shown) to the facsimile machine, this 16-paging signal is sent to the bypass circuit 212. , diode bridge circuit 213.16th detection circuit 214,
Changeover switch 216 and diode bridge circuit 21
3, and is thereby detected by the 16 city detection circuit 214. Then, a detection signal is generated from the 168Z detection circuit 214, and this fact is transmitted from the control circuit 210 to the central control circuit 70, which causes the central control circuit 70 to control the control circuit 5 of the facsimile terminal interface circuit 51.
A switching control instruction is output to 10. Then, a switching signal is generated from the control circuit 510 and the switching signal 512 is
is switched to the 16Hz generation circuit 513 side, and as a result, 1
A 16 Hz calling signal is generated from the 6H2 generating circuit 513 and sent to the facsimile machine 50, and as a result, the facsimile machine 50 is called. In response, when the facsimile machine [50 automatically responds, the terminal interface circuit 51
The DC current detection circuit 516 detects the current, and the central control circuit 70 is notified of this via the control circuit 510.

Then, a switching control instruction is sent from the central control circuit 70 to the control circuit 510, which causes the control circuit 510 to operate and switch the changeover switch 512 to the DC current generating circuit 514.
As a result, the facsimile device 50 is supplied with a loop current from the DC current generating circuit 514. The central control circuit 70 also issues a switching control instruction to the control circuit 210 of the office line interface circuit 21, thereby switching the changeover switches 211.21'6 to the diode bridge circuit 213 side and the DC loop circuit 215 side, respectively. Then, the tip line T and ring line R of the central office line 11
A DC loop is formed between the calling party and the facsimile machine 50, thereby establishing a connection between the calling party and the facsimile machine 50, allowing the facsimile machine 50 to communicate. Further, at this time, the formation of the DC loop is detected by the DC loop circuit 215, and this fact is notified to the central control circuit 70 via the control circuit 20.

Then, the central control circuit 7o controls each button telephone 31 to 3.
Display data indicating that the central office line 11 is in use is sent to m via the terminal interface circuits 41 to 4m. Therefore, it is no longer possible to access the central office line 11 using the button telephones Ia31-3m in this state.

Meanwhile, station 1m11 is connected to the facsimile network,
If a 1300Hz calling signal arrives in this state, this 1300H2 calling signal is detected by the 1300tlx detection circuit 217, and the detected data is sent to the control circuit 210.
is sent to the central control circuit 70 via. At this time, the above-mentioned 1300)lx calling signal is also sent to the 16 city detection circuit 214 via the bypass circuit 212 and diode bridge circuit 213, but the level of the 1300Hz calling signal is about -20 to -368m, which is about 16H2. Call signal (
75Vrms), so it is not detected. Now, when the above detection data is sent, the central control circuit 70 sends a switching control instruction to the control circuit 510 of the facsimile terminal interface circuit 51, and switches the changeover switch 5.
12 to the 16- generation circuit 513 side. For this reason,
A 16To signal is generated from the 16- generation circuit 513 and supplied to the facsimile machine 50, whereby the facsimile machine @50 is called. The subsequent operations are as described in 1 above.
This is the same as when a 6 Hz calling signal arrives at the central office line 11.

In this way, with this device, whether the central office line 11 is connected to a subscriber telephone network or a facsimile network, it is possible to detect a call from an exchange and transmit it to the facsimile machine to perform facsimile communication.

However, such a conventional device has a 1681 detection circuit and a 1300 detection circuit in the station line interface circuits 21 to 2n, respectively.
8Z detection circuits are provided, and these detection circuits provide 16
H2 and 1300) lx are detected and notified to the central control circuit 70 to operate the terminal interface circuit 51 and call the facsimile machine, so the configuration of the office line interface circuits 21 to 2n is Each of these methods is complicated, and the entire fruiting device becomes large and expensive.

Furthermore, regardless of whether a 16th or 1300 Hz calling signal arrives, the central control circuit 70 knows this by monitoring the office line interface circuits 21 to 2n and performs a series of controls. 70
There was a tendency for the burden to increase.

(Problems to be Solved by the Invention) ゛As described above, in the conventional device, all the detection of the calling signal is performed in the central office line interface circuit, which makes the configuration of the central office line interface circuit complicated, and this causes problems in the entire device. J
However, the present invention focuses on these problems and simplifies the configuration of the station line interface circuit, thereby making the entire device smaller and at a fixed price. The object of the present invention is to provide a button telephone device that can achieve the above-mentioned functions and reduce the burden on the central control circuit.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides that facsimile machines in recent years are equipped with a detection circuit for a specific facsimile call signal (1300 Hz) sent out by the facsimile network so that the facsimile machines can be connected to the facsimile network. Focusing on the fact that the number of things that people have is increasing, a facsimile call signal supply circuit A is provided in the office line interface circuit as shown in Fig. 1, and this circuit A receives the above-mentioned specific facsimile call signal coming from the office line side. The signal is supplied to the facsimile machine via the main signal path of the facsimile terminal interface circuit, and the central control circuit is notified by the facsimile terminal interface circuit that the specific facsimile ringing signal is detected by the facsimile machine. A facsimile connection control means B is provided which controls the central office line interface circuit and closes the direct current loop of the central office line when the central office line interface circuit is activated.

(Function) As a result, when connected to a facsimile network, a specific facsimile call signal that arrives at the central office line is directly supplied to the facsimile machine via the central office line interface circuit, crosspoint switch circuit, and facsimile terminal interface circuit. , since it is detected by the detection circuit of this facsimile machine, the branch line interface circuit does not need a circuit for detecting the specific facsimile call signal, which simplifies the configuration of the branch line interface circuit. This allows the overall configuration of the device to be made smaller and cheaper. Further, since the central control circuit does not need to perform control to notify the facsimile machine when a paging signal arrives, the burden on the central control circuit is reduced accordingly.

(Embodiment) FIG. 2 shows a circuit configuration of a button telephone device according to an embodiment of the present invention. In this figure, the same parts as in FIG. 4 are given the same reference numerals and detailed explanations will be omitted.

A signal passing circuit 21 serving as a facsimile call signal supply circuit is provided between the changeover switch 211 of the office line interface circuit 21' and the output terminal to the crosspoint switch 60.
9 is the setting. This signal passing circuit 219 is composed of a capacitor 219a and an audio transformer 218' connected in series, and allows the 1 300 Hz calling signal that has arrived at the office line 11 to pass through as it is and outputs it to the facsimile terminal interface circuit 51. The signal is supplied to the facsimile machine [50] through this circuit 51. Here, the capacitor 219
The capacitance of a is set so that the impedance is low for the 1301 calling signal and high for the 16- calling signal.

Further, the central control circuit 70', as the above-mentioned calling signal 1300- is directly supplied to the facsimile machine 50,
A control means is provided for controlling the connection of the facsimile machine accordingly.

Because of this configuration, the central office line 11 is currently connected to the facsimile network, and in this state, the 1300
When a 1300 Hz facsimile calling signal arrives, this 1300 Hz calling signal is supplied to the audio transformer 218' via the selector switch 211 and the capacitor 219a, and from the audio transformer 218' to the facsimile via the cross point switch 6o. It is sent to the terminal interface circuit 51. The audio transformer 511 and main signal line 51 of this terminal interface circuit 51
7 and then supplied to the facsimile machine 50.

In addition, in the above-mentioned office line interface circuit 21, 130
The 0fh calling signal is also supplied to the 16th detection circuit 214 via the bypass circuit 212 and the diode bridge circuit 213, but the level of the 1300Hz calling signal is very low compared to the 16th calling signal as described above. Since it is small, the 168X detection circuit 214 will not detect it incorrectly.

Then, when a 1300 Hz ringing signal is supplied to the facsimile machine 50, the facsimile apparatus 50 detects this ringing signal, automatically responds, and closes the internal DC loop circuit. Then, a DC current flows from the power supply 515 of the terminal interface circuit 51 to the facsimile machine 50 via the DC current detection circuit 516, the DC current generation circuit 514, the changeover switch 512, and the main signal line 517. Detected in The detection output is sent from the DC current detection circuit 516 to the control circuit 51.
0 to the central control circuit 70'.

As a result, the central control circuit 70' sends a switching control instruction to the control circuit 210 of the office line interface circuit 21', thereby switching the switching switches 211 and 216 to the diode bridge circuit 213 side and the DC loop circuit 215 side, respectively.
to form a direct current loop of the central line 11. Thus, facsimile communication between the calling party and the facsimile machine 150 is possible from now on.

In addition, the central office line 11 is connected to the subscriber telephone network, and thereby 1G
The operation when a Hz paging signal arrives is exactly the same as that of the conventional device described above.

In this way, in the device of this embodiment, the signal passing circuit 219 is provided in the office line interface circuit 21', and this circuit 2
19 allows the 1300th)+2 calling signal to pass through and directly supplies it to the facsimile machine 50 for detection, making it possible to eliminate the need for 1300th detection circuits from each of the office line interface circuits 21 to 2n.
By simplifying the structure of the branch line interface circuits 21 to 2n, the entire device can be made smaller and cheaper. Further, since there is no need to notify the facsimile machine 50 of the arrival of the paging signal of 1300H1, the control burden on the central control circuit 70' can be reduced accordingly. Furthermore, in this embodiment, a capacitor 219a whose capacitance is set so that the impedance is low for a 1300 H2 calling signal and high for a 16 Hz calling signal is provided in the signal passing circuit. , 16
When the city's calling signal arrives, the calling signal is prevented from being supplied to the transformer 218' at a high level, thereby reliably protecting the transformer 218' from burn-in or the like. Further, since most of the 16To calling signal is supplied as is to the 16Hz detection circuit 214, the detection sensitivity of the 11 calling signal can be increased. Note that the present invention is not limited to the above-mentioned embodiments, and the present invention also applies to, for example, the configuration of the facsimile ringing signal supply circuit, the configuration and number of installations of the office line interface circuit and the facsimile terminal interface circuit, connection control procedures, etc. Various modifications can be made without departing from the gist of the invention.

[Effects of the Invention] As detailed above, according to the present invention, a facsimile call signal supply circuit is provided in the office line interface circuit, and this circuit supplies the specific facsimile call signal received from the office line side to the facsimile terminal interface. When the facsimile device detects the specific facsimile call signal and is notified of this by the facsimile terminal interface circuit, the facsimile terminal interface circuit By providing a facsimile connection control means that controls the line interface circuit and closes the direct current loop of the office line, the configuration of the office line interface circuit can be simplified and the entire device can be downsized and priced at a fixed price. It is possible to provide a button telephone device that can reduce the burden on a central control circuit.

[Brief explanation of the drawing]

FIG. 1 is a functional block diagram showing the configuration of the present invention, FIG. 2 is a circuit configuration diagram showing a part of a button telephone device according to an embodiment of the present invention, and FIG. 3 is the overall configuration of a conventional button telephone device. FIG. 4 is a circuit block diagram showing a part of the device. A...Facsimile calling signal supply circuit, B...Call connection control means, 11-1n...Station line, T...Tip line, R...Ring line, 21'-2n+...・Central office line interface circuit (COU), 31-3m...Key telephone (EKT), 41-4m...Terminal interface circuit (STU) for button telephone, 50...
Facsimile machine (FAX), 51...fu? Terminal interface circuit (FSTU) for Kushimiri, 60...
Cross point switch (XP), 70'...Central control circuit (CCLJ), 80...Tone signal generator,
90...Power supply unit, 210.510...Control circuit (C
C), 211, 216.512... changeover switch, 2
12... Bypass circuit, 213... Diode bridge circuit, 214... 16Hz detection circuit, 215...
・DC loop circuit, 218', 511, 413°41
4...Transformer, 219...Signal passing circuit, 219
a... Capacitor, 411... Audio signal line, 41
2... Data signal line, 415... Interface circuit, 513... 16Hz generation circuit, 514... DC current generation circuit, 515... DC power supply, 516...
DC current detection circuit, 517... Main signal @ line.

Claims (2)

[Claims] (1) A facsimile machine is connected to a central office line interface circuit provided corresponding to a central office line, a plurality of terminal interface circuits to which key telephones are connected, and a facsimile machine equipped with a circuit for detecting a specific facsimile ringing signal. A facsimile terminal interface circuit, a cross-point switch circuit that selectively connects the office line interface circuit and each terminal interface circuit, and a cross-point switch circuit that controls these circuits to connect each of the button telephones or facsimile machines to the office line. and a central control circuit for selectively connecting between the facsimile device and the facsimile terminal interface circuit, and transmits a specific facsimile call signal received from the facsimile side to the facsimile terminal interface circuit through the main signal path of the facsimile terminal interface circuit. A facsimile call signal supply circuit is provided to supply the
and when the specific facsimile calling signal is detected by the facsimile machine and the facsimile terminal interface circuit notifies the central control circuit of the detection, the central control circuit controls the central office line interface circuit to close the DC loop of the central office line. A button telephone device characterized by being provided with facsimile connection control means. (2) The facsimile ringing signal supply circuit has a capacitor circuit whose impedance is low for a specific facsimile ringing signal and high for a 16Hz ringing signal. ) The button telephone device described in paragraph ).