JP2003111115A - Termination detecting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To connect a telephone exchange with analog line of public network without taking account of its polarity. SOLUTION: The termination detecting system being used in a telephone exchange comprises a termination detecting circuit 4-6 for detecting the polarity state of an analog line 7, and a circuit 4-7 for prestoring the polarity state of the analog line 7 under waiting state. Upon detecting variation in the polarity state of the analog line 7 from that stored in a storage circuit 4-7, a control circuit 4-5 notifies detection of termination to a central processing unit 5 by notifying termination detection information.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an incoming call detection system used in a telephone exchange or a key telephone device (hereinafter referred to as "telephone exchange device").

[0002]

2. Description of the Related Art An analog station line consisting of a two-wire cable provided from a public network supplies a battery (-48V) to the L1 line and a ground line to the L2 line in a standby state (normal state). is doing. Then, when the incoming call is made, L1
The ground is supplied to the line and the battery is supplied to the L2 line, which is a so-called polarity reversal state (reversal state), and then a call signal is sent.

Therefore, the telephone exchange device accommodating the analog office line detects that the analog office line of the public network has changed from the standby state to the polarity inversion state, and subsequently, the ringing signal is sent. Incoming is detected by detecting. In addition, before and after the ringing signal is sent, the polarity reversal of the analog station line is detected to prohibit outgoing calls using this analog station line and prevent collision between outgoing calls and incoming calls. It is carried out.

Next, a station line trunk provided with a conventional incoming call detection circuit (polarity inversion detection circuit) will be described.

FIG. 6 is a block diagram showing a station line trunk for accommodating an analog station line which is provided in a telephone exchange and is provided by a public network and which is composed of a two-wire cable.

In FIG. 6, the L1 line and the L2 line of the analog station line 7 composed of a two-wire cable provided from the public network.
The line is connected to the outgoing / incoming circuit 9-1 via the A terminal and the B terminal, respectively. This outgoing / incoming circuit 9-1
Forms a loop with the analog station line 7 at the time of transmission, and outputs a dial pulse when necessary.
A loop signal is formed at the start of a call by detecting a ringing signal transmitted from the analog station line 7 when an incoming call is received. Further, the 2/4 conversion circuit 9-2 is connected to the transmission / reception circuit 9-1. The 2/4 conversion circuit 9-2 is for converting the analog station line 7 which is two wires into a four-wire format signal composed of two wires in the transmission direction and two wires in the reception direction.

CODEC circuit 9-3
Are connected to the 2/4 conversion circuit 9-2 and the highway interface circuit (I / F) 9-4. The codec circuit 9-3 converts the analog signal from the 2/4 conversion circuit 9-2 into a digital signal and sends the digital signal to the highway interface circuit 9-4, and also receives the digital signal from the highway interface circuit 9-4. The signal is converted into an analog signal and sent to the 2/4 conversion circuit 9-2.
The highway interface circuit 9-4 interfaces with the highway provided from the time switch SW of the telephone exchange device.

The incoming call detection circuit 9-6 is connected to the L2 line of the analog office line 7. This incoming detection circuit 9-6 is
This is a circuit that detects that the L2 line has changed from ground to a battery (-48V) and that the analog station line 7 is in a polarity inversion state, and outputs an incoming call detection signal. Control circuit (MPU) 9-5
Is connected to the outgoing / incoming circuit 9-1, the codec circuit 9-3, and the incoming detection circuit 9-6, and is also connected to the central processing unit CCU of the telephone exchange. And
The control circuit 9-5 exchanges various control information with the central processing unit CCU to control the entire station line trunk 4,
Loop formation of incoming / outgoing circuit 9-1, incoming call detection processing,
The level adjustment process of the codec circuit 9-3 and the process of detecting the polarity reversal by the incoming call detection signal output from the incoming call detection circuit 9-6 are performed.

In such a configuration, the analog station line 7
When there is an incoming call from the incoming call detection circuit 9-6, an incoming call detection signal is output, which is read by the control circuit 9-5 and notified to the central processing unit CCU. Then, the central processing unit CCU performs a process of restricting the call from the analog office line 7 to prevent the collision between the call and the call. After this,
When a calling signal is transmitted from the analog office line 7, the calling / receiving circuit 9-1 detects this and the calling / receiving circuit 9
The control circuit 9-5 reads the detection of -1 and notifies the central processing unit CCU. Then, the central processing unit CCU performs the well-known incoming call processing of notifying the general telephone or the relay stand of the incoming call through the line circuit or the like.

[0010]

In the above-mentioned conventional technique, the incoming detection circuit of the office line trunk monitors only one line (L2 line) of the analog office line provided from the public network and checks its polarity reversal. Because it is recognized, A of the trunk line trunk
It was necessary to fixedly connect the L1 wire to the terminal and the L2 wire to the B terminal.

Therefore, if the terminals of the analog office line and the trunk of the office line are connected in reverse, the analog station line will be seen during the incoming call and the normal operation cannot be performed. For this reason,
When installing an analog office line to the terminal of the office line trunk during the installation work or line work of the telephone exchange device, the worker is aware of the polarity (L1 line and L2 line of the analog line) when working. Had to do.

The present invention has been made in view of the above problems, and an object thereof is to connect a telephone exchange device to an analog office line of a public network during installation work or line construction of the telephone exchange device. Another object of the present invention is to provide an incoming call detection method that enables connection without worrying about the polarity and that can easily perform confirmation work after installation work or line work.

[0013]

In order to achieve the above object, the present invention relates to an incoming call detection system used in a telephone exchange device which accommodates an analog line for inverting the polarity of the line when an incoming call arrives. Polarity detection means for detecting the state, storage means for storing the polarity state of the analog line in the standby state, and detection that the polarity state obtained from the polarity detection means has changed from the state stored in the storage means. The present invention is characterized by comprising polarity reversal detection means and, when the polarity reversal detection means detects polarity reversal, outgoing / incoming collision prevention means for preventing collision of outgoing and incoming calls on the analog line.

Therefore, according to the above configuration, it is possible to eliminate the polarity of connection when connecting the analog office line to the office line trunk in the telephone exchange.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a system diagram showing the configuration of a telephone exchange device to which the incoming call detection system of the present invention is applied.

In FIG. 1, the telephone exchange device includes a speech path switch (SW) 3 including a time switch, and a plurality of line circuits (LIN) accommodated in the speech path switch 3.
It comprises two and a plurality of office line trunks 4, a central processing unit (CCU) 5 for controlling the entire telephone switching equipment including the communication path switch 3, the line circuit 2 and the office line trunk 4.

The general telephone 1 is connected to each of the line circuits 2. The line circuit 2 is an interface device for connecting the general telephone 1 to the telephone exchange device, and controls transmission / reception of the general telephone 1. A public network 6 is connected to the office line trunk 4 via an analog office line 7 composed of a two-wire cable. The office line trunk 4 is an interface device for connecting an analog office line 7 provided by the public network 6 to a telephone exchange device, and controls outgoing / incoming of the analog office line 7.

FIG. 2 is a block diagram showing the configuration of the office line trunk 4 shown in FIG.

In FIG. 2, the office line trunk 4 is provided with A terminals and B terminals, and the L1 line and L2 line of the analog office line 7 consisting of a two-wire cable provided from the public network 6 are respectively A terminal and A transmitting / receiving circuit 4-through the B terminal, or the B terminal and the A terminal, which have become a telephone terminal.
Connected to 1. This outgoing / incoming circuit 4-1 forms a loop with the analog station line 7 at the time of outgoing, outputs a dial pulse as necessary, and also a calling signal sent from the analog station line 7 at the time of incoming. Is detected and a loop is formed at the start of a call. Also,
The 2/4 conversion circuit 4-2 is connected to the transmission / reception circuit 4-1. The 2/4 conversion circuit 4-2 is for converting the analog station line 7 which is two wires into a four-wire type signal composed of two wires in the transmitting direction and two wires in the receiving direction.

CODEC circuit 4-3
Are connected to the 2/4 conversion circuit 4-2 and the highway interface circuit (I / F) 4-4. The codec circuit 4-3 converts the analog signal from the 2/4 conversion circuit 4-2 into a digital signal and sends the digital signal to the highway interface circuit 4-4, and also outputs the digital signal from the highway interface circuit 4-4. The signal is converted into an analog signal and sent to the 2/4 conversion circuit 4-2.
The highway interface circuit 4-4 interfaces with the highway provided from the speech path switch 3 of the telephone exchange device.

The incoming call detection circuit 4-6 receives the L1 line and the L2 line of the analog station line 7 through the A terminal and the B terminal, respectively.
Alternatively, these are connected to the L2 line and the L1 line which are telecopies. In this incoming call detection circuit 4-6, the L1 line is a battery (-48V) and the L2 line is in a ground standby state, or L
This is a circuit that outputs an incoming call detection signal indicating whether the 1st line is ground and the 2nd line is the polarity reversal state in which the battery (-48V) is changed.
The control circuit (MPU) 4-5 is a transmission / reception circuit 4-1.
The codec circuit 4-3 and the incoming call detection circuit 4-6 are connected to the central processing unit 5 of the telephone exchange. Then, the control circuit 4-5 has a storage circuit 4-
In accordance with a control program stored in the storage circuit 4-7, the control circuit 4 exchanges various control information with the central processing unit 5 to control the entire trunk line trunk 4, and the transmission / reception circuit 4- 1, loop formation, incoming call detection processing, level adjustment processing of the codec circuit 4-3, and processing for detecting polarity reversal by the incoming call detection signal output from the incoming call detection circuit 4-6.

FIG. 3 is a circuit diagram showing the structure of the incoming call detection circuit 4-6 shown in FIG.

In FIG. 3, one terminal of the current limiting resistor R1 is connected to the A terminal, the other terminal of the resistor R1 is connected to the anode terminal of the photocoupler PC, and the photocoupler is further connected. The cathode terminal of PC is connected to the B terminal. Further, the cathode terminal of the diode D is connected to the anode terminal of the photocoupler PC, and the anode terminal of the diode D is connected to the cathode terminal of the photocoupler PC. Both of the currents to the A terminal are configured to flow.

The collector terminal of the photocoupler PC is connected to the + 5V power source line, and the emitter terminal of the photocoupler PC is connected to the ground via the current limiting resistor R2. Further, a capacitor C is connected in parallel to both ends of the resistor R2, and this capacitor C absorbs noise generated instantaneously. One terminal of the resistor R4 and one terminal of the resistor R5 are connected, and the resistor R4 and the resistor R5 are connected in series. The other terminal of the resistor R4 is connected to the + 5V power source line, and the other terminal of the resistor R5 is connected to the ground. The resistors R4 and R5, for example, add +2 to 3
A voltage dividing circuit for V is formed.

The non-inverting terminal (+) of the comparator CMP is connected to the emitter terminal of the photocoupler PC via the current limiting resistor R3. The inverting terminal (-) of the comparator CMP is connected to the connection point of the resistors R4 and R5. The output terminal of the comparator CMP is pulled up to the + 5V power supply line via the resistor R5 which is a pull-up resistor. The output terminal of the comparator CMP is connected to the control circuit 4-5 of the office line trunk 4, and the output from the comparator CMP is used as an incoming call detection signal.

In such a structure, when the battery (-48V) is applied to the A terminal and the ground is applied to the B terminal, the current from the B terminal is passed through the diode D and the resistor R1 to the A terminal. Therefore, the photocoupler PC is turned off. Therefore, the ground potential is visible at the non-inverting terminal of the comparator CMP, and the ground level (L level) is output from the comparator CMP according to the result of comparison with the reference voltage at the inverting terminal of the comparator CMP.

Also, the A terminal is grounded and the B terminal is a battery (-
48V) is applied to each
Since the current from the terminal flows through the resistor R1 and the photocoupler PC (from the anode terminal to the cathode terminal) to the B terminal, the photocoupler PC is turned on. Therefore, a potential of approximately +5 V can be seen at the non-inverting terminal of the comparator CMP,
Depending on the result of comparison with the reference voltage at the inverting terminal of the comparator CMP, the comparator CMP outputs + 5V level (H level).

As a result, the analog terminal line 7 is connected to the A terminal.
L1 line is connected, and the analog terminal line 7 is connected to the B terminal.
When the L2 line is connected, the analog station line 7 is in the standby state, the battery (-48V) is supplied to the L1 line, and the ground is supplied to the L2 line.
When the analog station line 7 is in the polarity inversion state (incoming state), the ground is supplied to the L1 line, and the battery (-48V) is supplied to the L2 line. The output from the comparator CMP becomes H level.

Also, the connection is changed to a teleco
The L2 line of the analog station line 7 is connected to the terminal, and B
When the L1 line of the analog station line 7 is connected to the terminal, the analog station line 7 is in a standby state, the battery (-48V) is supplied to the L1 line, and the ground is supplied to the L2 line. At this time, the output from the comparator CMP becomes H level,
On the other hand, the analog station line 7 is in the polarity reversal state (incoming call state), the ground is supplied to the L1 line, and the battery (−) is supplied to the L2 line.
48 V) is being supplied, the output from the comparator CMP becomes L level.

Next, the operation of the embodiment of the present invention will be described.

In FIG. 4, the L1 line of the analog office line 7 is connected to the A terminal of the office line trunk 4 and the analog office line 7 is connected to the B terminal.
Or the L2 line of the analog station line 7 is connected to the A terminal of the station line trunk 4 and the L1 line of the analog station line 7 is connected to the B terminal. Two
7 is a flowchart for recognizing whether or not the connection state is. In addition,
This shows the operation of the control circuit 4-5 of the office line trunk 4.

First, it is recognized that the L1 line and the L2 line of the analog office line 7 are connected to the A terminal and the B terminal of the office line trunk 4 (S4-1). After this, the comparator C
It is determined whether the output (incoming call detection signal) from the MP has continued for a certain period of time as L level or H level (S4-
2). If the analog station line 7 is in a standby state when it continues for a certain period of time, the output level from the comparator CMP at that time is stored in the control circuit 4-5. It is stored in the circuit 4-7 (S4-3). Therefore, for example, if the L1 line of the analog station line 7 is connected to the A terminal and the L2 line of the analog station line 7 is connected to the B terminal, the L level is stored as the level in the standby state, and A L2 line of analog station line 7 is connected to the terminal, and
When the L1 line of the analog office line 7 is connected to the terminal, the H level is stored as the level in the standby state.

The fixed time for determining that the analog office line is in the standby state can be set arbitrarily. This is because a fixed time for judging that the system is in the standby state is arbitrarily input in advance from a maintenance terminal device (not shown) provided in the telephone exchange device, and the central processing unit 5 reads this and reads the local line. This is performed by notifying the control circuit 4-5 of the trunk 4 and setting it in the memory circuit 4-7 by the control circuit 4-5. Further, the processing shown in FIG. 4 is performed not only at the start of online but also periodically during online operation.

FIG. 5 is a flow chart showing the incoming call processing of the office line trunk 4. This shows the operation of the control circuit 4-5 of the office line trunk 4.

First, the control circuit 4-5 periodically scans the output (incoming call detection signal) from the comparator CMP,
According to the flowchart shown in FIG. 4, it is detected whether the level has changed from the level of the initial value stored in advance (S5-1). That is, when an incoming call is made to the station line trunk 4, if the level of the initial value stored in advance is L level, it changes to H level, and the level of the initial value stored in advance is H level. If so, it changes to the L level, and by detecting this change, the polarity reversal of the analog office line 7 is recognized.

Here, when the control circuit 4-5 detects a change in the output level (incoming detection signal) from the comparator CMP,
Collision prevention processing is performed to notify the central processing unit 5 that an incoming call detection signal has been detected (S5-3). Upon recognizing the detection of the incoming call detection signal, the central processing unit 5 restricts (prohibits) outgoing calls using the station line trunk 4 and performs outgoing / incoming collision prevention processing for preventing a collision between outgoing calls and incoming calls.

Next, when a calling signal is sent out from the analog office line 7, the calling / receiving circuit 4-1 detects it and outputs it as a calling signal detection signal, so that the control circuit 4-5 makes a calling / receiving call. The circuit 4-1 is periodically scanned to detect the ringing signal detection signal from the outgoing / incoming circuit 4-1 (S5-3). Then, when the control circuit 4-5 detects the call signal detection signal from the call / call receiving circuit 4-1, the control circuit 4-5 performs a call receiving process for notifying the central processing unit 5 that the call signal has been detected (S5-4). . Then, the central processing unit 5
Performs a well-known incoming call processing of notifying the general telephone 1 and a relay stand (not shown) of the incoming call through the line circuit 2.

As a result, when the office line trunk 4 of the telephone exchange is connected to the analog office line 7 of the public network 6, the L1 line and the L2 line of the analog office line 7 are connected to each other in opposite polarities. Even the incoming call can be detected normally.

Although the present embodiment has been described by taking an analog office line of a public network as an example, the present invention provides an analog line (for example, a dedicated line) which is composed of a two-wire cable and which reverses the polarity of the line when receiving a call. The same can be applied to the same.

[0041]

As described above, according to the present invention, in the installation work or line construction of the telephone exchange device, when the telephone exchange device is connected to the analog office line of the public network, the connection can be made without paying attention to the polarity thereof. Also, the confirmation work after the installation work or the line work can be performed easily.

[Brief description of drawings]

FIG. 1 is a system diagram showing a configuration of a telephone exchange device to which an incoming call detection system of the present invention is applied.

FIG. 2 is a block diagram showing a configuration of a station line trunk shown in FIG.

FIG. 3 is a circuit diagram showing a configuration of an incoming call detection circuit shown in FIG.

FIG. 4 is a flowchart for recognizing a connection state between a station line trunk and an analog station line.

FIG. 5 is a flowchart showing an incoming call process of an office line trunk.

FIG. 6 is a block diagram showing a configuration of a conventional office line trunk.

[Explanation of symbols]

1 General telephone 2 line circuit 3 Call path switch 4 station trunk 5 Central processing unit 6 public network 7 analog station line 4-1 Send / receive circuit 4-2 2/4 conversion circuit 4-3 Cordic circuit 4-4 Highway interface circuit 4-5 Control circuit 4-6 Call detection circuit

Claims (3)

[Claims] 1. An incoming call detection system used in a telephone exchange that accommodates an analog line for reversing the polarity of the line when an incoming call arrives, comprising: polarity detecting means for detecting a polarity state of the analog line; and polarity of the analog line in a standby state. Storage means for storing a state, polarity inversion detection means for detecting that the polarity state obtained from the polarity detection means has changed from the state stored in the storage means, and the polarity inversion detection means for detecting polarity inversion Then, an incoming / outgoing call collision preventing means for preventing a collision between an outgoing call and an incoming call on the analog line is provided. 2. A standby polarity setting means for storing the polarity status obtained from the polarity detection means in the storage means as the polarity status of the analog line in the standby status when the polarity status continues for a predetermined time. The incoming call detection method according to claim 1, wherein 3. The incoming call detecting method according to claim 2, wherein the standby polarity setting means periodically detects whether or not the polarity state obtained from the polarity detecting means continues for a predetermined time. .