JPH04264898A - Truck line incoming call connection system - Google Patents

Abstract

PURPOSE:To enable an incoming call connection with an original caller corresponding to a calling return from 110 number or 119 number, as for a trunk line incoming call connection system of a private branch exchange having the central office of a 2 line type analog telephone line. CONSTITUTION:A central office 1 of the pertinent private branch exchange is equipped with a calling signal detecting circuit 2 which detects a calling signal at the time of an incoming call, and a direct current reversed polarity detecting circuit 3 which detects the state of a trunk line switchboard 10 before receiving the calling signal, and closes a transmission. The pertinent direct current reversed polarity detecting circuit 3 is equipped with a means which detects again the state of the trunk line switchboard 10 after the calling signal is detected by the calling signal detecting circuit 2, and communicates the detected result to a processing processor 9. When the direct current voltage polarity of the 2 line type analog telephone line is the empty of the line and the reversed polarity at the time of receiving the calling signal, the normal incoming call connection is operated, and when the direct current voltage polarity of the 2 line type analog telephone line is the empty of the line and the like-polarity at the time of receiving the calling signal, a previously transmitted extension is called.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a central office line termination connection system for a private branch exchange having a central office line trunk connected to a two-wire analog telephone line. Generally, in a private branch exchange, in response to an incoming call from a central office line, the central office line relay board or a specific extension is called in response to the paging signal, and when the central office relay board or specific extension responds, the call is returned to the central office line where the call came from. performs an action to return a response. Conventionally, private branch exchanges have been set in such a way that when a paging signal arrives from a central office line, it calls a central office relay stand or a predetermined extension.

However, if a telephone extension calls 110 (police) or 119 (fire) through a private branch exchange, and the extension telephone is restored first, even if a call-back signal is sent from the central office exchange. , 110 and 11
It was not possible to connect directly to the phone that dialed number 9 using the private branch exchange. Therefore, a switchboard or a predetermined telephone located at a different location from the originating telephone is called,
There was an inconvenience in that it was not possible to connect to the most important calling telephone, and it took time to search for the caller. However, when making an emergency 110 or 119 call, it is becoming necessary for private branch exchanges to connect directly to the caller in response to a call back from a police station or fire department for confirmation.

0003

2. Description of the Related Art FIG. 4 shows a diagram of a connection state from a conventional central office exchange to terminal equipment (private branch exchange, etc.). Figure (a) is for an idle connection, Figure (b) is for a normal incoming call, and Figure (c) is for a 1
This shows the case of a callback on the 10th line or the 119th line. In the figure, 21 is terminal equipment (private branch exchange, etc.), 22 is a central exchange subscriber circuit, 23 is a calling signal circuit, 24 is a calling signal sending circuit, 25 is a response detection circuit, 26 is a reverse circuit, 27 is a power supply circuit, 28 indicates a network.

In the case of the empty connection shown in FIG.
The power supply and the earth are connected to the subscriber's line to monitor the subscriber side, and a loop circuit is formed by the outgoing connection of the terminal equipment 21, and the dial pulse signal is received and connected to the network 2.
8 to the central office exchange subscriber. If the subscriber of the central office responds, the response signal is connected to the terminal equipment 21 by the reversal of the reverse circuit 26, and a call state is established. Figure (b)
In the case of a normal incoming call, when there is an incoming call from the central office exchange subscriber circuit 22 to the terminal equipment 21, the reverse circuit 26 is reversed,
A calling signal is sent from the calling signal circuit 23 to the terminal equipment 21 by the relay operation of the calling signal sending circuit 24, and the response detection circuit 25 is activated by the response from the terminal equipment 21 side, and the relay of the calling signal sending circuit 24 is restored. , the subscriber of the central office exchange and the subscriber of the terminal equipment can communicate via the power supply circuit 27 and the network 28.

[0005] In the case of the callback shown in Figure (c), terminal equipment 2
When there is a call from 1 to the subscriber circuit 22 of the central exchange, the reverse circuit 26 does not reverse due to the response from the central office, and the communication between subscriber No. 110 or 119 of the central exchange and the terminal equipment 21 is established, and the terminal equipment 21 disconnects the connection, the station side processes the call while remaining on hold, and if it is necessary to call again, a ringing signal is sent from the ringing signal circuit 23 by the relay operation of the ringing signal sending circuit 24 of the subscriber circuit 22. is sent to the terminal equipment 22 side. If the terminal equipment 21 responds, the station and the caller can talk again. However, if the terminal equipment is a private branch exchange, the private branch exchange recovers once the caller disconnects, so when the private branch exchange is called again by a paging signal from the central office exchange, it calls the switchboard or a predetermined subscriber. Put it away.

In general, when the two-wire analog telephone line of a central office exchange is idle, the power supply circuit 27 connects one of the two wires L1 to earth (ground potential) and the other wire L1.
A DC voltage with negative polarity 2 is applied to the terminal equipment 21 side. When the terminal equipment 21 side and the station side subscriber are connected, the power supply circuit 27 becomes a through state. In the case of a normal incoming call to the terminal equipment 21, since L1 and L2 are reversed, a DC voltage of the opposite polarity to the above-mentioned idle state is applied to the terminal equipment 2.
2 side, and the earth air on which the call signal 23 is superimposed is connected to the line L2 on the battery side. On the other hand, in the case of a callback to the 110th line or the 119th line, since L1 and L2 are not reversed, a DC voltage of the same polarity as in the above-mentioned vacant case is applied to the terminal equipment 21 side, and the A ringing signal is applied to line L1.

That is, the DC voltage applied to the two-wire analog line has opposite polarity when receiving a normal call and when calling back from a 110 or 119 call.

[0008]

[Problems to be Solved by the Invention] With conventional private branch exchanges, calls such as 110 or
If the extension phone is restored first after dialing 19, even if a call back signal is sent from the central office exchange, the 11
It was not possible to connect directly to the phone that dialed 0 or 119.

An object of the present invention is to enable a direct connection to the telephone that made the 110 or 119 call in response to a callback when the 110 or 119 call is made. Therefore, as mentioned above, the direct current voltage applied to the two-wire analog line is of opposite polarity when receiving a normal call at the central office exchange and when calling back from a 110 or 119 number. Incoming calls will be identified at the exchange.

0010

[Means for Solving the Problems] A diagram of the principle configuration of the present invention is shown in FIG. In the figure, 1 is a private branch exchange central office line trunk;
2 is a calling signal detection circuit, 3 is a DC reverse polarity detection circuit when receiving a calling signal, 4 is a DC loop formation and selection signal sending circuit, 5 is a DC loop formation relay circuit, 6 is a response signal detection circuit when making a call, 7 8 is a private branch exchange network, 9 is a private branch exchange processing processor, and 10 is a central office exchange (
A is the state when the connection is idle, B is the state when a normal call is received, and C is the state when the call is received.
10 or 119).

In the private branch exchange office line trunk 1, after a calling signal is detected by the calling signal detection circuit 2, the DC reverse polarity detection circuit 3 compares the polarity of the DC voltage of the line with the state C when the connection is idle. Is it normal incoming call A status?
The system is configured to perform incoming call processing by determining whether it is in the callback state B from 110 or 119.

0012

[Operation] A processing flowchart of the present invention is shown in FIG. Figure (a) shows a central office line termination connection system of the present invention, and Figure (b) shows a conventional central office line termination connection system. The figure shows the processing flow when an incoming call is connected in the private branch exchange central office line trunk 1.

The central office line incoming call connection system of the present invention shown in FIG. Check if it is the same as Jiki. ■
If the polarity from L1 is applied to a voltage that is different from the ground voltage in state A when the connection is open, the DC reverse polarity detection circuit 3
detects the call signal, blocks outgoing connections from other subscribers, and monitors the call signal in the call signal detection circuit 2. ■ If the polarity from L1 is the same as in state A during the idle connection, the DC reverse polarity detection circuit 3 does not detect it, so it is determined that an incoming connection has been established, and the calling signal detection circuit 2 detects the incoming connection from L2. Or detect a call signal from L1. (2) After detecting the calling signal, the DC reverse polarity detection circuit 3 checks whether the polarity from L1 is the same as the voltage in state A during the idle connection or a different voltage. ■ If it detects that the polarity is a voltage opposite to state A when the connection is idle, it is determined that the connection state is B, and preset processing (connection to a central office line relay board or connection to a set extension line) is performed. conduct. (2) If it is detected that the polarity is the same as state A when the connection is idle, it is determined that the connection state is C, and processing is performed to call the extension that was called to that office line immediately before.

[0014] In the conventional central office line incoming call connection system shown in FIG. Check to see if it is the same as the Jiki. ■'L
If a voltage is applied that is different from the ground voltage when the polarity from 1 is in state A when the connection is open, the DC reverse polarity detection circuit 3 detects it and blocks the outgoing connection from other subscribers. A calling signal detection circuit 2 monitors the calling signal. ■If the polarity from L1 is the same as the polarity in state A when there is an empty connection, the DC reverse polarity detection circuit 3 does not detect it, so it determines that the incoming connection is established and detects the ringing signal. Circuit 2 detects a calling signal from L1 or L2. (2) After detecting the calling signal, preset processing (connection to the central office line relay board or connection to the set extension line) is performed. Therefore, 110 or 11
Even in the case of a call back from number 9, the same processing as for a normal incoming connection was performed.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 3 shows an embodiment of a block diagram of a private branch exchange according to the present invention. In the figure, 11 is a private branch exchange central office line trunk, 12 is a ringing signal detection circuit (RG), 13 is a DC reverse polarity detection circuit (SP), 14 is a DC loop formation and selection signal sending circuit (AL), and 15 is a DC loop. 16 is a response signal detection circuit (R) at the time of transmission.
V), 17 is a speech path (SPN), 18 is a private branch exchange network (NW), and 19 is a private branch exchange processing processor (
CPU).

In the figure, a paging signal detection circuit 12 detects a paging signal from a central office exchange at the time of incoming call, and outputs a paging signal to a processor 19.
The DC reverse polarity detection circuit 13 detects the state of the L1 line from the central office exchange, detects the battery from the central office side, and sends a detection signal to the processor 19. The DC loop forming relay circuit 15 is operated by a signal from the processor 19 at the time of a call, and forms a loop circuit on the central office exchange side through the b contact and disconnects the calling signal detection circuit 12. The DC loop forming and selection signal sending circuit 14 forms a DC loop on the central office exchange side, and sends out dial pulses or selection signals during outgoing calls by connecting and disconnecting the a-contact. Response signal detection circuit 16
detects a response signal (reverse) from the originating exchange and sends a response signal from the terminating side to the processor 19. The communication path 17 connects the subscriber of the private branch exchange and the subscriber of the central office exchange via the network 18.

In the above circuit, the conventional DC reverse polarity detection circuit 13 used before receiving the calling signal is also used after receiving the calling signal to determine whether the incoming connection is a normal incoming connection or a callback connection from 110 or 119. The processor 19 then processes the destination. Therefore, by simply adding processing within the processor and without changing the circuitry of a conventional private branch exchange, incoming connection processing can be identified by monitoring the connection status on the central exchange side.

[0018]

Effects of the Invention As mentioned above, with conventional private branch exchanges, it was not possible to connect to the original caller in response to a call back from 110 or 119. In the case of a call back (reverse call) from a telephone number or 119 line, it is possible to connect to the extension that made the call just before, and even in a private branch exchange, it is possible to connect to the original caller in response to a call back.

[Brief explanation of the drawing]

[Figure 1] Principle configuration diagram of the present invention

[Figure 2] Processing flowchart of the present invention

[Figure 3]
Block configuration diagram of the embodiment

[Figure 4] Connection status diagram of central office exchange

[Explanation of symbols]

1, 11 Private branch exchange central office line trunk 2, 12 Call signal detection circuit 3, 13 DC reverse polarity detection circuit 4, 14 DC loop formation and selection signal sending circuit 5
, 15 DC loop forming relay circuit 6, 16 Response signal detection circuit 7, 17 Communication path 8, 18 Private branch exchange network 9, 19 Private branch exchange processing processor 10 Central exchange 21 Terminal equipment (private branch exchange, etc.) 22 Central exchange subscriber circuit 23 Calling signal circuit 24 Calling signal sending circuit 25 Response detection circuit 26 Reverse circuit 27 Power supply circuit 28 Network

Claims (1)

[Claims] 1. A private branch exchange having a central office line trunk of a two-wire analog telephone line, the central office trunk (1) of the private branch exchange having a ringing signal detection circuit (2) for detecting a ringing signal at the time of incoming call; Central exchange before receiving the calling signal (10
DC reverse polarity detection circuit (
3), and after the DC reverse polarity detection circuit (3) detects the calling signal in the calling signal detection circuit (2), it detects the state of the central office line exchange (10) again and sends the processing processor (9) If the DC voltage polarity of the two-wire analog telephone line is opposite to that when the line is idle when a ringing signal is received, a normal incoming connection is made; An incoming call connection system for private branch exchanges that is characterized in that if the polarity of the DC voltage is the same as when the line is vacant, the most recently called extension is called.