JPH06181586A - Exchanging device for direct inward dialing trunk line - Google Patents

Abstract

PURPOSE:To provide an exchanging device surely operated at a high speed whose circuit constitution is simple by providing a CPU for controlling a signal detection circuit, a line relay, a discrimination circuit, a relay driving circuit, a ring signal generation circuit and a privacy telephone circuit. CONSTITUTION:In the exchanging device 10 for a direct inward dialing trunk line, the calling signals of a telephone transmitted from the main line 11 of a telephone station are detected at the signal detection circuit 12. Its output is received, the line relay 13 is thrown in, connection to the discrimination circuit 14 is performed and the circuit 14 analyzes and compares push-button PB signals transmitted from the telephone station. Its compared result is outputted to the relay driving circuit 17, changeover to prescribed slave telephones 15 and 16 is performed at the circuit 17 and at the same time, the bell of the slave telephone 15 (16) is rung. Also, when one of the slave telephones 15 (16) is busy, the privacy circuit 19 is operated, the connection of the other slave telephone 15 (16) is cut off and the leakage of speech is prevented. The respective circuits are controlled by control circuits 20 provided with the CPU 22, simple constitution is attained and operations can be surely performed at a high speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dial-in exchange line switching apparatus for connecting a single line circuit of a telephone station to two or three sub-phones by dividing the number.

[0002]

2. Description of the Related Art Conventionally, it has been practiced to use an extension telephone having a number larger than the number of lines by interposing a switching device between a small number of telephone lines and extension telephones. However, such a method requires an exchanging device and an exchanging operator, which is very troublesome. Therefore, in recent years, in order to perform these automations, a service (dial-in service) in which a small number of lines are provided with telephone numbers larger than the number of lines and a PB signal corresponding to the telephone number is sent at the timing of the connection sequence by the central office The exchange that secures a large number (for example, 120) of different telephone numbers from a plurality of lines (for example, 12 lines) by receiving this service, and connects to the telephone corresponding to the telephone number. The device was being developed.

[0003]

However, although the above switching device is highly useful in a company having a large number of lines, it has only a small number of lines such as one or two. It is not useful as a large-scale and expensive device in a small-scale store or individual home. Also, there is a switching device that can secure the telephone numbers of two or three telephones from one line using the services of the telephone office and automatically switch and use them by the control equipped with the CPU. It was never developed.
The present invention has been made in view of the above circumstances, and operates reliably with a simple configuration and utilizes the services of a central office to connect the telephone numbers of two or three telephones with one line. An object of the present invention is to provide a switching device for a dial-in office line which is secured and can be automatically selected by a device provided on the user side and which is inexpensive.

[0004]

A method according to the above-mentioned object.
The dial-in office line switching device described is a dial-in office line switching device for switching and connecting two or three slave phones with one main line, and a telephone sent by the main line. A signal detecting circuit for detecting the ringing signal of the line, a line relay which is turned on by receiving the output of the signal detecting circuit, and a PB signal which is connected to the main line when the line relay is turned on and which is sent after the ringing signal. A discriminating circuit for analyzing and comparing with a set value, a relay drive circuit for switching the sub-phone by the output of the discriminating circuit, a ring signal generating circuit for calling the sub-phone switched by the relay drive circuit, and each of the above A secret circuit that is provided between the sub-phone and the main line to disconnect the sub-phone that is not in a call state, and the signal detection circuit, line relay, discrimination circuit, relay drive circuit, ring signal generation circuit And it is constituted by a control circuit having a CPU for controlling each circuit of the scrambler circuit.
Here, the PB signal is a push button signal (push).
Also referred to as “button signal”, it refers to a signal used for a subscriber line signal.

[0005]

In the dial-in office line switching apparatus according to the present invention, the signal detecting circuit detects the telephone call signal sent from the main line of the central office and receives the output of the signal detecting circuit. Turn on the line relay and connect to the discrimination circuit.
Then, the discriminating circuit analyzes and compares the PB signal transmitted from the telephone station. The result of the comparison is output to the relay driving circuit, and at the same time when the relay driving circuit switches to a predetermined sub-phone, the ring signal generating circuit operates to ring the bell of the sub-phone. Also, when one child phone is in a call, the confidential circuit operates to prevent the other child phone from disconnecting and disconnecting the call. Each of the circuits is controlled by a control circuit including a CPU (hereinafter, simply referred to as a CPU control circuit), has a simple structure, and can operate at high speed and reliably.

[0006]

Embodiments of the present invention will now be described with reference to the accompanying drawings to provide an understanding of the present invention. Here, FIG. 1 is a block diagram of a switching device for a dial-in office line according to an embodiment of the present invention, FIG. 2 is the same wiring diagram, and FIG.
Is a wiring diagram of the CPU control circuit of the exchange device for the dial-in station line, FIG. 4 is a wiring diagram of the discrimination circuit, the timer circuit, the AMP circuit and the DC loop circuit, and FIG. 5 is the same secret circuit, relay drive circuit and 16 Hz detection. Circuit wiring diagram, Figure 6 is the same 16Hz
Wiring diagrams of the bell signal circuit, the power supply holding circuit and the power supply circuit, FIG. 7 is a flow chart used for explaining the operation of the exchange device for the dial-in station line, and FIG. 8 is used for explaining the operation of the exchange device for the dial-in station line. It is a flowchart to do.
As shown in FIGS. 1 and 2, a dial-in office line switching apparatus 10 according to an embodiment of the present invention detects a telephone call signal sent from a central office line (main line) 11 of a central office. 16 Hz detection circuit 12 which is an example of a signal detection circuit,
A line relay 13 that receives the output of the Hz detection circuit 12 and a discrimination circuit that analyzes a subscriber line signal (hereinafter referred to as a PB signal) sent from the station line 11 after a calling signal and compares it with a set value. 14 and a relay drive circuit 17 for switching the sub-phones 15 and 16 by the output of the discrimination circuit 14.
And a 16 Hz bell signal circuit 18 which is an example of a ring signal generation circuit for calling the switched sub-phones 15 and (16), and is provided between the sub-phones 15 and 16 and the central office line 11. Secret circuit (also called loop detection circuit) 19
And each of the circuits 12, 13, 14, 17, 18 and 19
And a CPU control circuit 20 (shown separately in FIG. 1 for the sake of explanation).

In FIG. 1, all the contacts are in the OFF state. The 16 Hz detection circuit 12 uses the photo coupler 2 to convert the 16 Hz signal of the ringing signal sent from the station line 11 at 16 Hz generated when the other party makes a call.
In step 1, the detection signal is sent to the CPU control circuit 20. The CPU control circuit 20, as shown in FIG.
A PU 22, a ROM 23, a RAM 24 and a reset switch 25 are provided, a program is written in the ROM 23, the RAM 24 temporarily stores data, and the CPU 22
Each circuit 12, 13, 14, 1 based on the program
Controls 7, 18 and 19 are performed. Then, the CPU 22 receives the detection signal, outputs it to the line relay 13, operates the line relay 13, turns on the relay contact 26, and holds the state. Since the relay contact 26 is closed, the low impedance transformer 3
1 is loaded, and via the DC loop circuit 27 on the secondary side,
A closed loop is formed between the station lines 11. At the same time as detecting the closed loop at the telephone office, a PB signal is sent. This PB signal is a service provided by the telephone station (NTT), and when the station line 11 is one line, a plurality of numbers are given to the line and the other party sets this telephone number to make a call. In the case of a loop, it is a signal for transmitting the last 1 to 4 digits corresponding to the telephone number immediately after entering the loop state. The discrimination circuit 14 comprises a DTMF receiver 28 and a setting comparison circuit 29 each connected to the CPU control circuit 20, and the DTMF receiver 28 detects a DTMF tone and outputs it as 4-bit data. I'm using it. And DTM
The F receiver 28 converts the PB signal transmitted from the station line 11 into a digital signal, and the CPU 22 compares and analyzes the signal and the set value A and the set value B preset by the digital switch 30 of the setting comparison circuit 29. Is done. The PB signal received by the DTMF receiver 28 is transmitted through the DC loop circuit 27, transformed by the transformer 31, and further amplified by the AMP circuit 32. The discrimination circuit 14 outputs the result of the determination to the CPU
It is transmitted to the control circuit 20. The relay drive circuit 17 is
In response to the result, the CPU 22 operates by the output, the line relay 33 or the line relay 34 is operated, and the relay contacts 35 and 36 are turned on and off to activate the slave phones 15 and 1.
6 is switched.

The 16 Hz bell signal circuit 18 is used for the sub telephone 1
This is a circuit for calling 5 and 16, and the 16 Hz detection circuit 12 detects a 16 Hz signal and activates the relay drive circuit 17 via the CPU 22 and simultaneously generates a ring signal. The 16 Hz bell signal circuit 18 is
As shown in FIG. 1 and FIG. 6, a voltage of about 200 V (may be lower than that) is generated on the secondary side by the transformer 47, and a high voltage of 16 Hz is applied to one of the sub-phones 15 and 16 to call it. It is designed to send out signals. At the same time, the transmission of the calling signal restores the relay contact 26 to the OFF state. Further, when either one of the sub-phones 15 and 16 is picked up, the impedance becomes a low impedance load, and the hall element 48 (current sensor) operates to operate the CPU 2 of the CPU control circuit 20.
2 sends a stop signal to the 16 Hz bell signal circuit 18 to stop the ring. The confidential circuit 19 has hall elements 37 and 38 (current sensors) each connected to the CPU 22, and when either one of the child phones 15 and 16 is picked up, either hall element 37 or 38 operates. Then C
The line relay 33 or the line relay 34 on the other side is operated via the PU control circuit 20 to open the relay contact 35 or the relay contact 36 to open the other sub-phone 15, (16 ) The call is not leaked.

In the call state, the hall element 3
Since any one of 7 and 38 is operating, the entire circuit of the dial-in station line switching device 10 is locked through the CPU control circuit 20 so that incoming calls cannot be received. When the bell rings and neither handset of the calling sub-phone 15 or 16 is picked up, a setting is made by the digital switch 40 of the timer circuit 39 operating via the CPU 22 simultaneously with the operation of the setting comparison circuit 29. The entire dial-in exchange line switching apparatus 10 is reset via the CPU 22 by a time-out signal generated by the passage of the set time (for example, 30 seconds). An element 41 for absorbing surge and a protection resistor 42 for the surge are connected to the station line 11 so that even if a high voltage is induced in the circuit by lightning or the like, it can be absorbed. Power supply holding circuit 4
3 corresponds to a sub-phone of a model in which the data registered in the sub-phones 15 and 16 in the standby state is stored by the power supply of the office line 11, so that a voltage of output 48V is supplied to the relay contact 45 operated by the line relay 44. It is a circuit to do.
46 is a power supply circuit.

Subsequently, the exchange device 10 for dial-in office line
The operation will be described with reference to the flowcharts shown in FIGS. 7 and 8. In advance, using the digital switch 30,
Numbers up to 4 digits are read as the set value A and the set value B into the RAM 24 through the setting comparison circuit 29 (step 1,
2). Since the ring signal is not sent from the telephone office, the timer circuit 39, which operates at the same time as the operation of the setting comparison circuit 29, does not take any of the slave phones 15 and 16, how long (for example, 30 seconds). ) The ring is rung, and then the time signal is transmitted to the CPU control circuit 20 to reset the entire dial-in station line switching device 10 by using the digital switch 40 to set the ring number reading (step 3). Then, the CPU 22 activates the line relay 44 to activate the relay contact 4
5 is turned on to disconnect the connection between the office line 11 and the confidential circuit 19, and at the same time, 48 V is supplied to the waiting sub-phones 15 and 16 to retain the registered data (step 4).
The 16 Hz detection circuit 12 judges whether or not the call signal from the station line 11 is received by the photo coupler 21 (step 5). If the call signal is detected and YES, the CPU 2
2 activates the line relay 13 and the relay contact 26
Is turned on (step 6). Then, the timer circuit 39
The time of 6 seconds set in step 3 is activated (step 7).
Since the relay contact 26 is turned on, the DC loop circuit 27 becomes a closed circuit, and the low impedance transformer 31
Is loaded into a loop state, and the telephone office detects this state, and at the same time, a PB signal is transmitted via the central office line 11. The PB signal is transformed by the transformer 31 and then A
It is amplified by the MP circuit 32 and transmitted to the determination circuit 14.

Then, in the discrimination circuit 14, the amplified P
The B signal is received by the DTMF receiver 28. The received signal is transmitted to the CPU control circuit 20 as a DTMF signal, and the presence or absence of the signal is determined by the CPU 22 (step 8). When the reception of the PB signal is YES, the RAM 24 temporarily stores the digital signal (step 9) and returns to the step 8. In step 8 again, the CPU 22 confirms that another DTMF signal is not transmitted. If YES, the flow from step 9 to step 8 is repeated. When the DTMF signal is not present as NO, the CPU 22 determines whether the time set in the timer circuit 39 in step 10 is, for example, 6 seconds (step 10). The judgment is N
In the case of O, the process returns to step 8 and the determination as to the presence or absence of the DTMF signal is performed again.

When the determination in step 10 is YES and the time is over, the CPU 22 performs a comparative analysis between the set value A set in the setting comparison circuit 29 and the signal received by the DTMF receiver 28 and converted into a digital signal. (Step 11). As a result of the analysis, if the set value A coincides with YES, the CPU 22 operates the line relay 13 to turn off the relay contact 26 (step 12), and the CPU 22 causes the line relay 33 to operate.
To turn on the relay contact 35 (step 13)
The connection with the hall element 37 is cut off. Then, the 16 Hz bell signal circuit 18 is activated to generate a ring (step 1
4). For example, the ring is sent once for 1 second and for 1 second for 2 seconds rest.
The CPU 22 determines whether or not a time of 30 seconds, for example, 10 cycles set in the timer circuit 39 has elapsed, which consists of a ring signal of the cycle (step 1).
5). If 30 seconds has elapsed, the CPU 22 operates the line relay 33 to turn off the relay contact 35 in step 16 and returns to the standby state before step 5 in step 16.

Further, in step 15, the judgment as to whether or not the number of times of ring setting is the number of times of ring setting is N
If it is O, the telephone bell is ringing and it is judged whether the hall element 48 is ON (step 1).
7) If the hall element 48 is not in the ON state, the result is NO and the process returns to step 14 to continue ringing the ring,
Repeat 4 or less. Pick up the handset of the sub-phone 15, turn on the hall element 48, and if YES (step 1
7) The CPU 22 sends a ring stop signal to the 16 Hz bell signal circuit 18, and the CPU 22 operates the line relay 33 to turn off the relay contact 35 (step 18).
Then, the CPU 22 operates the line relay 34 to turn on the relay contact 36 (step 19) to disconnect the connection of the slave telephone 16. Then, the CPU 22 causes the line relay 44
Is activated, the relay contact 45 is turned off, the station line 11 and the sub-phone 15 are connected, and a call state is established (step 20).
Further, the CPU 22 determines whether or not the hall element 37 is turned off (step 21), and if the answer is NO and the child phone 15 is in the call state, the determination of step 21 is repeated. In step 21, the child phone 1
Place the handset 5 and hang up the phone to open the Hall element 37 OF
In the case of F, the CPU 22 operates the line relay 44 to turn on the relay contact 45 (step 22), and the station line 11
Disconnect from. Next, the CPU 22 sets the line relay 3
4 is activated and the relay contact 36 is turned off (step 2
3) Then, the process returns to the front of step 5 and enters the standby state.

Further, in step 11, in the comparison analysis of the set value A set in the setting comparison circuit 29 and the signal value received by the DTMF receiver 28 and converted into a digital signal, the set value A does not match and the result is NO. CPU if available
It is determined whether or not 22 matches the signal value of the DTMF receiver 28 and the setting B set in the setting comparison circuit 29 (step 24). If the determination is YES as a match with the set value B, the CPU 22 determines that the line relay 1
3 operates to turn off the relay contact 26 (step 25), and the CPU 22 operates the line relay 34 to turn on the relay contact 36 (step 26) to disconnect the slave telephone 16. Then, the CPU 22 operates the 16 Hz bell signal circuit 18 to generate a ring as in step 14 (step 27). Then, the CPU 22 judges whether or not the number of times the ring has been set, for example, 10 cycles for 30 seconds set by the timer circuit 39 (step 28), and if the handset of the child phone 16 is not picked up even after 30 seconds, it is timed out and YES. Then, the CPU 22 operates the line relay 34 to turn off the relay contact 36 (step 29), and step 5
It returns to the front and comes to a standby state.

If it is determined in step 28 that the number of rings has not been reached and the determination is NO, the hall element 48 is turned on via the CPU 22 in step 30.
If the Hall element 48 is OFF, the process returns to step 27 and the steps from step 27 onward are repeated. When the hall element 48 is ON and YES (step 30), when the handset of the child phone 16 is picked up, C
The PU 22 sends a stop signal to the 16 Hz bell signal circuit 18 and the ring stops ringing. Then, the CPU 22 causes the line relay 3
4 is activated to turn off the relay contact 36 (step 3
1) Further, the CPU 22 operates the line relay 33 to turn on the relay contact 35 (step 32), the sub telephone 15
Disconnect. Then, the CPU 22 causes the line relay 44
Is activated to turn off the relay contact 45 (step 33) to connect the station line 11 and the sub-telephone 16 and bring them into a call state. Further, in step 34, the CPU 22 determines whether the hall element 38 is OFF. Hall element 3
If 8 is ON, the determination of step 34 is repeated again. In addition, the hall element 38 is OFF and YE
If the answer is S, the call is over and the handset of the child phone 16 is placed, so that the CPU 22 causes the line relay 44 to operate.
To activate the relay contact 45 (step 3
5), disconnect from the station line 11. And the CPU 22
Activates the line relay 33 and the relay contact 35 turns off.
Then, the process returns to the step before step 5 and enters the standby state.

In step 24, if the signal value of the DTMF receiver 28 and the setting value B of the setting comparison circuit 29 do not match, the CPU 22 determines NO, and the timer circuit 39 sets a count of, for example, 6 seconds. It starts with a 6 second time ON (step 37). Then C
It is judged whether or not the PU 22 is over the time (step 38), and if NO is determined and the time is not over, step 38 is repeated. On the other hand, if the answer is YES and the time is over, the CPU 22 operates the line relay 13 to turn off the relay contact 26 (step 39) and returns to the standby state before step 5.

Further, in step 5, the 16 Hz detection circuit 12 via the CPU 22 determines that the incoming signal of the ringing signal from the station line 11 via the photo coupler 21 is N.
When it is determined to be O (step 5), the CPU 22 determines whether the hall element 37 is ON (step 40), and when YES is determined to be ON, the flow from step 19 onward is followed. If the determination in step 40 is NO because the hall element 37 is OFF, it is determined whether the hall element 38 is ON by the CPU 22 (step 41). If the hall element 38 is ON, YES is determined and the flow following step 32 is followed. Hall element 3
If 8 is OFF, the determination is NO, and step 5
The following flow will be followed.

Depending on the recent terminal equipment, there is a model that operates with a slight signal, and a call signal sent from the telephone office (NTT) may cause a malfunction by a slight signal until the 16 Hz detection circuit 12 operates. Because there is
CP is applied to the relay contact 45 of the line relay 44 when the power is turned on.
It is operated by the signal of the U control circuit 20. Also,
When the sub-phones 15 and 16 pick up the handset, the hall element 3
Since CPUs 7 and 38 operate, the CPU 2 of the CPU control circuit 20
2, the relay contact 45 is operated via the line relay 44 to connect the office line 11 to any one of the sub-telephones 15 and 16. Next, as a measure against the runaway of the CPU 22, a reset switch 25 is provided so that the CPU 22 can be easily reset. In the present embodiment, the case where there are two slave phones has been described, but even when there are three slave phones, as shown in FIGS. 1 and 2, the digital switch 30 and the relay drive of the setting comparison circuit 29 are driven. This can be easily implemented by adding a circuit such as a line relay of the circuit 17 and a hall element of the confidential circuit 19 and changing the data of the CPU control circuit.

[0019]

According to the dial-in station line switching apparatus of the present invention, a CPU control circuit for controlling each circuit of a signal detection circuit, a line relay, a discrimination circuit, a relay drive circuit, a ring signal generation circuit, and a confidential circuit. Since it is used, it is possible to provide an excellent exchange device which has a simple circuit configuration and operates at high speed and reliably at a low price.

[Brief description of drawings]

FIG. 1 is a block diagram of a dial-in office line switching device according to an embodiment of the present invention.

FIG. 2 is a wiring diagram of the same.

FIG. 3 is a wiring diagram of a CPU control circuit of the exchange device for the dial-in office line.

FIG. 4 is a wiring diagram of the determination circuit, the timer circuit, the AMP circuit, and the DC loop circuit.

FIG. 5 is a wiring diagram of the secret communication circuit, the relay drive circuit, and the 16 Hz detection circuit.

FIG. 6 is a wiring diagram of the 16 Hz bell signal circuit, the power supply holding circuit, and the power supply circuit.

FIG. 7 is a flowchart used for explaining an operation of the exchange device for the dial-in office line.

FIG. 8 is a flowchart used for explaining an operation of the exchange device for the dial-in central office line.

[Explanation of symbols]

 10 Dial-in Switch for Line Switch 11 Station Line 12 16Hz Detection Circuit 13 Line Relay 14 Discrimination Circuit 15 Sub-phone 16 Sub-phone 17 Relay Drive Circuit 18 16Hz Bell Signal Circuit 19 Secret Circuit 20 CPU Control Circuit 21 Photocoupler 22 CPU 23 ROM 24 RAM 25 Reset Switch 26 Relay Contact 27 DC Loop Circuit 28 DTMF Receiver 29 Setting Comparison Circuit 30 Digital Switch 31 Transformer 32 AMP Circuit 33 Line Relay 34 Line Relay 35 Relay Contact 36 Relay Contact 37 Hall Element 38 Hall Element 39 Timer Circuit 40 Digital Switch 41 Element 42 Protection resistance 43 Power supply holding circuit 44 Line relay 45 Relay contact 46 Power supply circuit 47 Transformer 48 Hall element

Claims (1)

[Claims] 1. A dial-in exchange line switching device for switching and connecting two or three sub-telephones with one main line, and detecting a ringing signal of a telephone sent by the main line. A signal detection circuit, a line relay that is turned on by receiving the output of the signal detection circuit, and a line relay that is connected to the main line when the line relay is turned on and is sent after a ringing signal.
A discriminating circuit for analyzing the B signal and comparing it with a set value, a relay drive circuit for switching the sub-telephone by the output of the discriminating circuit, and a ring signal generating circuit for calling the sub-phone switched by the relay drive circuit. A secret communication circuit provided between each of the slave phones and the main line to cut off the connection of the slave phones not in a call state, and the signal detection circuit, line relay, discrimination circuit, relay drive circuit, ring signal generation circuit and secret communication circuit And a control circuit having a CPU for controlling each circuit of the above.