JP7733873B2 - Emergency call device - Google Patents

Description

This invention relates to an emergency notification device that makes emergency calls to emergency call receiving organizations such as police agencies, fire departments, and the Japan Coast Guard.

For example, in the event of an emergency such as a fire, an emergency notification device is known that sends an emergency notification to a designated emergency notification receiving agency, such as a fire department. When the caller presses a notification button, the emergency notification device calls the emergency notification receiving agency, connects the call line, and automatically notifies the emergency using a pre-prepared voice message. The emergency notification receiving agency then calls back to a special number answering dedicated telephone (hereinafter referred to as a dedicated telephone) connected to the emergency notification device. In response, the caller can pick up the handset of the dedicated telephone, which will ring, and then go off-hook, connecting the call line between the dedicated telephone and the emergency notification receiving agency, allowing the call to be made.

If the emergency call device is connected to an analog telephone network (PSTN (Public Switched Telephone Network)), the call line between the emergency call receiving agency and the emergency call device is placed on hold after the emergency call is made. Therefore, when the emergency call receiving agency calls back, a call signal (hereinafter referred to as an IR signal) is sent over the analog telephone network, causing the dedicated telephone to ring. In response, by picking up the handset of the dedicated telephone, the caller can speak to a representative at the emergency call receiving agency. In this way, when the call is on hold and the caller hangs up, the emergency call receiving agency sounds a ringtone. This is called a "reverse call."

In recent years, it has become possible to use IP (Internet Protocol) networks. An IP network refers to a network interconnected using the Internet Protocol Suite (TCP/IP). When operating an emergency call device connected to an IP network, the line hold function after an emergency call is no longer available. Instead, a system is adopted in which the caller is called back (called back) to a dedicated telephone, which connects the line and enables a call to be made. Patent Document 1, described below, discloses an invention related to an emergency call device that can connect the line and make a call in response to a call from an emergency call receiving agency, even if the telephone connected to the emergency call device that makes an emergency call via an IP network is off-hook.

Japanese Patent Application Laid-Open No. 2022-62919

As mentioned above, while IP networks are becoming more widely used, traditional analog telephone networks are also widely used. It has been discovered that in the case of emergency notification devices connected to analog telephone networks, connecting a regular telephone to the emergency notification device in addition to a dedicated telephone can cause inconvenience. For example, as shown in Figure 7, in addition to a dedicated telephone 2, a regular telephone (including a business phone, etc.) 3 may be connected to the emergency notification device 1X. By doing so, settings for the emergency notification device 1X make it possible to respond to calls (return calls) from the emergency notification receiving agency 5 through the regular telephone 3, creating an environment in which calls can be more reliably responded to.

However, as shown in Figure 7, the general telephone 3 can be connected to the analog telephone network 4 via the emergency call device 1X, and can make and receive calls to and from the external telephone 6 at times other than when making an emergency call. The general telephone 3 is placed, for example, on a desk and is frequently used under normal circumstances, so the user may unintentionally leave it off the hook. Let's assume that the general telephone 3 is off the hook when making an emergency call. In this case, the emergency call is made normally, but the line between the emergency call device 1X and the emergency call receiving agency 5 is on hold, and if the general telephone 3 is off the hook (off-hook), the off-hook general telephone 3 will automatically answer the return call, unintentionally, without the caller's intention.

In other words, a call line is connected between the general telephone 3 and the emergency call receiving agency 5, preventing the dedicated telephone 2 or the general telephone 3 from ringing, and the caller being unable to notice the call back and unable to respond to it. It is considered unlikely that the general telephone 3 is not busy and is unintentionally off the hook when an emergency call is made, but due to the characteristics of the emergency call device 1X, it is desirable to ensure that the caller is able to notice the call back.

In light of the above, the object of this invention is to ensure that when multiple telephones are connected to an emergency call device that makes emergency calls via an analog telephone network, even if some of the telephones are off-hook, the occurrence of a reverse call can be reliably reported (notified) through an on-hook telephone.

In order to solve the above problem, the emergency call device of the invention described in claim 1 comprises:
An emergency call device to which a plurality of telephones for making calls to an emergency call receiving agency are connected, and which makes an emergency call to the emergency call receiving agency through an analog telephone network,
a call detection means for detecting the arrival of a call signal from the analog telephone network after an emergency call is made;
a line monitoring means for monitoring signals from the analog telephone network and detecting whether or not a telephone is off the hook among the plurality of telephones connected to the line monitoring means;
a hook state detection means for detecting the hook state of each of the plurality of telephone sets connected to the own device;
a switching means for switching between connection and non-connection to the analog telephone network for each of the plurality of telephones connected to the own device;
and control means for controlling said switching means so that, when the incoming call signal is detected by said reverse call detection means and the presence of a telephone set in an off-hook state is detected by said line monitoring means, the telephone set in an off-hook state is disconnected from said analog telephone network and the telephone set in an on-hook state is connected to said analog telephone network based on the detection output of said hook state detection means.

According to the emergency call device described in claim 1, the emergency call device is connected to multiple telephones for making calls to an emergency call receiving agency and makes emergency calls to the emergency call receiving agency via an analog telephone network. When the incoming call detection means detects the arrival of a call signal and the line monitoring means detects the presence of an off-hook telephone, the control means controls the switching means based on the detection output of the hook state detection means. In this case, the control means controls the switching means to disconnect off-hook telephones from the analog telephone network and connect on-hook telephones to the analog telephone network.

According to this invention, multiple telephones are connected to an emergency call device that makes emergency calls via an analog telephone network. Even if one of the multiple telephones is off-hook after an emergency call is made, the off-hook telephone can be prevented from automatically responding to a call back. Furthermore, the occurrence of a call back can be reliably notified via an on-hook telephone. This allows the caller to connect a call line to the emergency call receiving agency via the on-hook telephone, make a call, and provide detailed information about the emergency situation.

1 is a block diagram illustrating a schematic configuration of an emergency notification device according to an embodiment. 2 is a block diagram for explaining the details of the configuration of the emergency notification device according to the embodiment. FIG. 3 is a sequence diagram for explaining a basic operation of the emergency notification device of the embodiment when making an emergency call. FIG. 10 is a sequence diagram for explaining a case where the emergency notification device of the embodiment operates without causing any problems when making an emergency call. FIG. FIG. 10 is a sequence diagram for explaining a problem that occurs when the general telephone 3 is off the hook in the operation of a conventional emergency notification device when making an emergency call. 4 is a flowchart illustrating details of a process performed in the emergency notification device according to the embodiment. FIG. 1 is a diagram illustrating an example of a conventional emergency notification system.

An embodiment of an emergency notification device according to the present invention will now be described with reference to the drawings. The emergency notification device of the embodiment described below is connected to an analog telephone network and has multiple telephones connected to it that can respond to a callback. A feature of the emergency notification device of the embodiment described below is that even if one of the telephones connected to the device goes off-hook after an emergency call is made, the occurrence of a callback can be reported through other on-hook telephones.

The emergency call receiving organization to which an emergency call is made is generally a police agency, fire department, or Japan Coast Guard, but it is of course possible for any other organization, such as a security company, to be the emergency call receiving organization. For simplicity's sake, the following embodiments will be described using an example in which the emergency call device reports the occurrence of a fire and the emergency call receiving organization is a fire department.

[General configuration of emergency notification device 1]
FIG. 1 is a block diagram illustrating the schematic configuration of an emergency call device 1 according to an embodiment. The emergency call device 1 is used in the same manner as the emergency call device 1X shown in FIG. 7. That is, as shown in FIG. 1, the emergency call device 1 according to this embodiment can make an emergency call by connecting a call line to an emergency call receiving agency 5 via an analog telephone network 4. The analog telephone network 4 refers to a public switched telephone network (PSTN), which enables analog-transmission voice calls between subscribers.

The emergency notification device 1 is connected to a dedicated telephone 2 and a regular telephone 3, similar to the case of the emergency notification device 1X shown in Figure 7. The dedicated telephone 2 and regular telephone 3 function as emergency call telephones for responding to calls received from the emergency notification receiving agency. The dedicated telephone 2 is a special number answering telephone that only functions to respond to calls received from the emergency notification receiving agency. Although not shown in Figure 1, the regular telephone 3 is also connected to the analog telephone network 4 through the emergency notification device 1, similar to the case shown in Figure 7, and is capable of making calls to desired parties and answering incoming calls under normal circumstances.

In other words, the emergency notification device 1 of this embodiment constitutes an emergency notification system in the same manner as the emergency notification device 1X shown in Figure 7. Also, in this example, the general telephone 3 is connected to the analog telephone network 4 via the secondary line of the emergency notification device 1, but this is not limited to this. The general telephone 3 may also constitute a business phone system, in which case it will be connected to the emergency notification device 1 and the analog telephone network 4 via a so-called main unit.

As shown in FIG. 1, the emergency notification device 1 comprises a line control unit 101, a telephone control unit 102, a CPU unit 103, and a notification button 104. The line control unit 101 controls the connection of the line through the analog telephone network 4, and comprises a line monitoring unit 1011, a call back detection unit 1012, and a notification control unit 1013. The telephone control unit 102 controls the connection between the line connected to the emergency notification device 1 and the dedicated telephone 2 or the general telephone 3, and comprises a hook state detection unit 1021 and a line connection control unit 1022.

The CPU 103 is a main control unit that controls each part of the emergency notification device 1, and although not shown, is configured with a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), non-volatile memory, etc. The notification button 104 is a button switch that is pressed by the caller.

[Details of the configuration of the emergency notification device 1]
2 is a block diagram for explaining the detailed configuration of the emergency notification device 1 according to the embodiment. For simplicity, the CPU 103 and the notification button 104 are omitted from FIG. 2. As shown in FIG. 2, the line monitoring unit 1011, the reverse call detection unit 1012, and the notification control unit 1013 of the line control unit 101 are each connected to the analog telephone network 4 and function under the control of the CPU 103.

When the report button 104 is pressed, the report control unit 1013, under the control of the CPU unit 103, places a call to a specified emergency report receiving agency 5, and if there is a response, sends a specified voice message (report message), and then disconnects the line. Note that even if the report control unit 1013 disconnects the line, the call line connected via the analog telephone network 4 is placed on hold.

After an emergency call is made by the call control unit 1013, the call back detection unit 1012 detects an IR signal (call back signal) sent from the analog telephone network 4 to the emergency call device 1 in response to the call back operation performed by the emergency call receiving agency 5. The IR signal has a cycle of 3 seconds, and is a continuous signal that is on for 1 second and off for 2 seconds. When the call back detection unit 1012 detects (receives) an IR signal, it notifies the telephone control unit 102 that an IR signal has arrived.

By monitoring signals from the analog telephone network 4, the line monitoring unit 1011 detects when at least one of the dedicated telephone 2 and the general telephone 3 connected to the emergency notification device 1 is in an off-hook state. In other words, when either the dedicated telephone 2 or the general telephone 3 goes off-hook, the off-hook telephone is connected to the analog telephone network 4 and seizes the line. In response, the analog telephone network 4 transmits a dial tone (DT) to the off-hook telephone.

A dial tone is the continuous "beep" sound that you first hear when you lift the receiver of a telephone. This allows you to make a call by entering the recipient's phone number when the telephone is off-hook. The dial tone is transmitted from the analog telephone network 4 for 30 seconds, but if you do not dial or make a call during this time, a busy tone will be transmitted from the analog telephone network 4 for 60 seconds.

A busy tone is typically the intermittent "beep beep" sound you hear when you make a call and the other party is busy. Since you cannot dial while a busy tone is being transmitted, you must replace the handset, put it back on-hook, then go off-hook again to make the call. However, if the busy tone is transmitted for 60 seconds without the call going on-hook, the analog telephone network 4, i.e., the central office, determines that the call has been taken off-hook or that a subscriber line has failed, and cuts off the 48V (volt) power supply.

If the line monitoring unit 1011 receives a dial tone or a busy tone, it determines that one of the telephones connected to its own device is off-hook and notifies the telephone control unit 102 of this. Also, suppose that the line monitoring unit 1011 receives a 30-second dial tone, followed by a 60-second busy tone, causing power supply from the analog telephone network 4 to be stopped.

When a subscriber line is placed on invalid hold for a long period of time, the state in which the analog telephone network 4 cuts off its power supply is called high and dry. Even if the power supply is stopped and the state becomes high and dry after going through a series of such states, the line monitoring unit 1011 determines that one of the telephones connected to its own device (emergency notification device 1) is in an off-hook state and notifies the telephone control unit 102 of this.

As described above, the telephone control unit 102 includes a hook state detection unit 1021 and a line connection control unit 1022. The hook state detection unit 1021 detects the hook state of the dedicated telephone 2, for example, based on voltage changes in the telephone line connected to the dedicated telephone 2, and detects the hook state of the general telephone 3 based on the voltage state of the telephone line connected to the general telephone 3. The hook state detection unit 1021 notifies the line connection control unit 1022 of the detected hook states of the dedicated telephone 2 and the general telephone 3.

As shown in FIG. 2, the line connection control unit 1022 includes a switching unit (switch circuit) 221 and a switching control unit 222. As shown in FIG. 2, the switching unit 221 has terminal N connected to the analog telephone network 4, terminal a connected to the dedicated telephone 2, and terminal b connected to the general telephone 3, and switches between connection and non-connection to the analog telephone network 4 for the dedicated telephone 2 and the general telephone 3. As shown in FIG. 2, the switching control unit 222 controls the switching of the switching unit 221 based on the detection output from the back call detection unit 1012, the detection output from the line monitoring unit 1011, and the detection output from the hook state detection unit 1021.

[Basic operation of emergency notification device 1]
The basic operation of the emergency notification device 1 having the configuration shown in Figures 1 and 2 when making an emergency notification will be described. Figure 3 is a sequence diagram for explaining the basic operation of the emergency notification device 1 of the embodiment when making an emergency notification. When the notification button 104 is pressed, a predetermined electrical signal is supplied to the CPU unit 103, and the CPU unit 103 is notified that the notification button has been operated. The CPU unit 103 instructs the line control unit 101 to make an emergency notification. In response to this, the notification control unit 1013 functions, and in this embodiment, the special number "119" for the emergency notification receiving agency 5, which is a fire department, is dialed to make the emergency notification (step S1).

The analog telephone network 4, i.e., the telephone exchange, transmits a call signal to the emergency call receiving agency 5 to receive the call (step S2). When the emergency call receiving agency 5 receives the call signal, a ringer connected to the emergency call receiving agency's command console (not shown) sounds, notifying the emergency call receiving agency 5 that an emergency call has been made. When the call is answered via the command console, a response signal is sent to the analog telephone network 4 (step S3), and the response signal is then transmitted from the analog telephone network 4 to the emergency call device 1 (step S4).

In the emergency notification device 1 that receives the response signal, the notification control unit 1013 functions to connect a call line between the emergency notification device 1 and the emergency notification receiving agency 5 via the analog telephone network 4, and in this example, sends a voice message notifying the occurrence of a fire (step S5). The voice message includes, for example, the address and name of the person reporting the fire, and is stored in advance in, for example, the non-volatile memory of the CPU unit 103. After sending the voice message notifying the occurrence of a fire, the notification control unit 1013 sends a disconnection signal to the analog telephone network 4 (step S6), which is then sent to the emergency notification receiving agency 5 via the analog telephone network 4 (step S7). This allows the emergency notification receiving agency 5 to recognize the end of the transmission of the notification message.

In Figure 2, the processing from step S8 onwards, shown below the dotted line, is the call back operation. In this case, the call line connected between the emergency call device 1 and the emergency call receiving agency 5 via the analog telephone network 4 is not disconnected, but is instead held. When the emergency call receiving agency 5 performs a call back operation via its control console, an IR signal (call back signal), which is a call signal, is sent to the analog telephone network 4 (step S8), and the IR signal is transmitted from the analog telephone network 4 to the emergency call device 1 (step S9). The IR signal transmitted from the analog telephone network 4 to the emergency call device 1 is detected by the call back detection unit 1012. That is, after an emergency call is made, the call back detection unit 1012 detects the IR signal transmitted in response to the call back operation by the emergency call receiving agency 5, and if detected, notifies the telephone control unit 102 that the IR signal has been detected.

In this case, it is assumed that dedicated telephone 2 and general telephone 3 are both on-hook. The hook states of dedicated telephone 2 and general telephone 3 are detected by hook state detection unit 1021 and notified to switching control unit 222 of line connection control unit 1022. Furthermore, since dedicated telephone 2 and general telephone 3 are on-hook, line monitoring unit 1011 does not detect that either dedicated telephone 2 or general telephone 3 is off-hook. As a result, no detection output is supplied from line monitoring unit 1011 to switching control unit 222, or it indicates that no telephone is in an off-hook state.

In this case, the switching control unit 222 of the line connection control unit 1022 controls the switching unit 221 to connect the dedicated telephone 2 and the general telephone 3 to the analog telephone network 4 (steps S10 and S11). As a result, an IR signal is supplied to each of the dedicated telephone 2 and the general telephone 3, causing the dedicated telephone 2 and the general telephone 3, which are on-hook, to ring (steps S12 and S13). This allows the occurrence of a reverse call from the emergency call receiving agency 5 to be notified through both the dedicated telephone 2 and the general telephone 3.

In this example, the caller presses the call button 104 on the emergency call device 1 and then picks up the handset (transmitter/receiver) of the dedicated telephone 2, putting the dedicated telephone 2 off-hook. In this case, a response signal is sent from the dedicated telephone 2 to the emergency call device 1 (step S14), a response signal is sent from the emergency call device 1 to the analog telephone network 4 (step S15), and a response signal is sent from the analog telephone network 4 to the emergency call receiving agency 5 (step S16).

This connects the call line between the dedicated telephone 2 and the emergency call receiving agency 5 (step S17), enabling voice communication. In this case, the caller can use the dedicated telephone 2 to notify the emergency call receiving agency staff of details of the fire, such as where the fire is and what type of fire it is, by voice call. After this, when the notification (report) of the fire details is complete, the handset of the dedicated telephone 2 is returned to its original state, and the dedicated telephone 2 is returned to the on-hook state.

In this case, a disconnection signal is sent from the dedicated telephone 2 to the emergency call device 1 (step S18), a disconnection signal is sent from the emergency call device 1 to the analog telephone network 4 (step S19), and a disconnection signal is sent from the analog telephone network 4 to the emergency call receiving agency 5 (step S20). As a result, the call line connected between the dedicated telephone 2 and the emergency call receiving agency 5 is disconnected (released).

In this way, the emergency call device 1 can make an emergency call to the emergency call receiving agency 5 when the call button 104 is pressed. In this case, the emergency call receiving agency 5 can make a call back, for example, through the dedicated telephone 2 to communicate with the caller, and understand the status of the emergency - in this example, the status of a fire - through a voice call. Note that the sequence diagram shown in Figure 3 explains the case where the call back is responded to through the dedicated telephone 2, but if the call is responded to through the general telephone 3, a voice call can be made with the emergency call receiving agency 5 through the general telephone 3 to inform them of the status of the fire, etc.

[Operation when the general telephone 3 connected to the emergency notification device 1 is off the hook]
4 is a sequence diagram for explaining the operation of the emergency call device 1 that makes an emergency call when the general telephone 3 is off the hook. As described above, the general telephone 3 is connected to the emergency call device 1, and is capable of responding to a call from the emergency call receiving agency 5 when making an emergency call, and is also capable of making external and internal calls under normal circumstances.

For example, consider the case where a call is made from a regular telephone 3 to an outside telephone 6 connected to the analog telephone network 4. In this case, as shown in Figure 4, the regular telephone 3 is taken off-hook, and a dial tone is returned from the analog telephone network 4. The user then enters the telephone number of the desired caller and dials the number (step S31). In this case, a call signal for the incoming call is sent from the analog telephone network 4 to the called outside telephone 6 (step S32). This causes the on-hook outside telephone 6 to ring, and when the user takes the outside telephone 6 off-hook, a response signal is sent to the analog telephone network 4 (step S33), and the analog telephone network 4 then transmits the response signal to the calling regular telephone 3 (step S34).

As a result, a call line is connected between the originating general telephone 3 and the destination external telephone 6 via the analog telephone network 4, enabling voice communication (step S35). After this, assume that the call ends and the user of the external telephone 6 puts the external telephone 6 on-hook. In this case, a disconnection signal is sent from the external telephone 6 to the analog telephone network 4 (step S36), and a disconnection signal is sent from the analog telephone network 4 to the originating general telephone 3 (step S37). As a result, the call line connected between the general telephone 3 and the external telephone 6 is released.

However, suppose the user of the general telephone 3 fails to properly return the handset to its designated position on the main body of the general telephone 3, leaving the general telephone 3 in an off-hook state. The hook states of the dedicated telephone 2 and the general telephone 3 are also detected by the hook state detection unit 1021, and are notified to the switching control unit 222. Therefore, under the control of the switching control unit 222 in response to the detection result of the hook state detection unit 1021, the switching unit 221 switches the general telephone 3, which is in an off-hook state, to connect it to the analog telephone network 4.

In this case, assume that a fire has broken out and the report button 104 on the emergency call device 1 is pressed. In the sequence diagram of Figure 4, steps S1 to S9 are the same as steps S1 to S9 in the sequence diagram of the basic operation shown in Figure 3. Therefore, the emergency call device 1 calls the emergency call receiving agency 5 (steps S1, S2), and when the emergency call receiving agency 5 answers (steps S3, S4), a telephone line is connected between the emergency call device 1 and the emergency call receiving agency 5.

The emergency notification device 1 transmits a voice message to the emergency notification receiving agency 5 via the connected call line to notify them of the occurrence of an emergency (step S5), and after transmission, transmits a disconnection signal to the emergency notification receiving agency 5 (steps S6 and S7). In this case, the connected call line is not disconnected, but is placed on hold. The subsequent processing is the call-back operation. That is, when the emergency notification receiving agency 5 performs a call-back operation, an IR signal is transmitted from the analog telephone network 4 to the emergency notification device 1 (steps S8 and S9).

In this case, as described above, the general telephone 3 is off-hook, so the line monitoring unit 1011 detects that either the dedicated telephone 2 or the general telephone 3 connected to the emergency notification device 1 is off-hook. Furthermore, the reverse call detection unit 1012 detects that an IR signal has arrived. Therefore, the switching control unit 222 is notified by the line monitoring unit 1011 that there is an off-hook telephone, by the reverse call detection unit 1012 that an IR signal has arrived, and by the hook state detection unit 1021 the hook state of each telephone.

For this reason, the switching control unit 222 of the emergency notification device 1 in this embodiment first controls the switching unit 221 based on the detection result from the hook state detection unit 1021 to disconnect the currently off-hook general telephone 3 from the analog telephone network 4 (step S41). In other words, the switching unit 221 disconnects terminal b from terminal N, and the general telephone 3 becomes unconnected to the analog telephone network 4. Note that in Figure 4, the disconnection of the general telephone 3 that was connected to the analog telephone network 4 from the analog telephone network 4 is indicated by a dotted arrow and a cross. This prevents an IR signal from being supplied to a general telephone 3 that is unintentionally off-hook, preventing the general telephone 3 from automatically responding to an IR signal and connecting the call line.

Next, the switching control unit 222 controls the switching unit 221 to connect the dedicated telephone 2, which is in the on-hook state, to the analog telephone network 4 (step S42). That is, the switching unit 221 connects terminal a and terminal N, and the dedicated telephone 2 is connected to the analog telephone network 4. As a result, an IR signal is supplied from the analog telephone network 4 to the dedicated telephone 2, which is in the on-hook state, and the dedicated telephone 2, which is in the on-hook state, rings to indicate an incoming call (step S43).

Therefore, suppose that a call back (an incoming call from an emergency call receiving agency) is notified through the dedicated telephone 2, which is on-hook, and the caller picks up the handset of the dedicated telephone 2 and goes off-hook. In this case, a response signal is returned from the dedicated telephone 2 to the emergency call device 1 (step S44), the emergency call device 1 sends the response signal to the analog telephone network 4 (step S45), and the analog telephone network 4 transmits the response signal to the emergency call receiving agency 5 that originated the call back (step S46).

As a result, a call line is connected between the dedicated telephone 2 and the emergency call receiving agency 5, enabling communication (step S47). This allows the caller, etc., to make a voice call with a person at the emergency call receiving agency 5 via the dedicated telephone 2 and report the details of the emergency (fire) situation, etc. Note that the term "caller, etc." is intended to include the caller and anyone who is near the dedicated telephone 2 and can respond to a call back.

Note that Figure 4 illustrates an example in which the general telephone 3 has gone off the hook. As mentioned above, the general telephone 3 is capable of both external and internal calls, and is normally used frequently, making it highly likely to go off the hook. However, this is not the only possible scenario. For example, if for some reason the dedicated telephone 2 is off the hook and the general telephone 3 is on-hook, the dedicated telephone 2 can be disconnected from the analog telephone network 4 and the general telephone 3 can be connected to the analog telephone network 4, just as in the case explained using Figure 4. In this case, the general telephone can be made to ring in response to an incoming call and then taken off-hook, connecting a call line to the emergency call receiving agency 5 and allowing a detailed call to be made.

[Details of the problems occurring in the conventional emergency notification device 1X]
For comparison, the operation of a conventional emergency notification device 1X will now be described. Fig. 5 is a sequence diagram for explaining a problem that occurs when the general telephone 3 is off the hook during operation of the conventional emergency notification device 1X during an emergency call. In Fig. 5, the processing from step S31 to step S37 is performed in the same manner as the processing from step S31 to step S37 in Fig. 4, and it is assumed that the general telephone 3 is off the hook.

In this case, assume that the report button is pressed and an emergency call is made. In this case, the processing from step S1 to step S9 in Figure 5 is performed in the same way as the processing from step S1 to step S9 in Figure 4. The processing from step S51 onwards differs from the processing in the sequence diagram shown in Figure 4.

That is, after an emergency call is made, an IR signal is sent to emergency call device 1X in response to a call back operation at emergency call receiving agency 5. Emergency call device 1X does not have functions such as line monitoring unit 1011, so it connects dedicated telephone 2 to analog telephone network 4 (step S51) and connects general telephone 3 to analog telephone network 4 (step S52). In this case, dedicated telephone 2 is on-hook, but general telephone 3 is off-hook, so a response signal from general telephone 3 is automatically returned to emergency call device 1 (step S53). This response signal is sent from emergency call device 1 to analog telephone network 4 (step S54), and then from analog telephone network 4 to emergency call receiving agency 5 (step S55).

As a result, a call line is connected between the general telephone 3 and the emergency call receiving agency 5 (step S56), making it possible to make a call. However, the general telephone 3 is unintentionally in an off-hook state, and the user is not able to talk to a representative at the emergency call receiving agency 5 through the general telephone 3. Also, as shown in Figure 5, in response to a return call from the emergency call receiving agency 5, a call line is immediately connected between the off-hook general telephone 3 and the emergency call receiving agency 5, so the dedicated telephone 2, which is on-hook, does not ring in response to the IR signal.

As a result, the caller, etc., cannot be notified of the occurrence of a reverse call through either the dedicated telephone 2 or the general telephone 3. Therefore, in the state shown in Figure 5, the caller, etc., cannot communicate with the person in charge at the emergency call receiving agency 5 through the call line that is connected in response to the reverse call from the emergency call receiving agency 5. As a result, the details of the emergency situation (details of the fire in this embodiment) cannot be communicated to the person in charge at the emergency call receiving agency 5, which may cause inconvenience such as delays in the emergency call receiving agency's appropriate response.

However, as explained using Figure 4, even if one of the telephones connected to the emergency call device 1 is off-hook after an emergency call is made, that off-hook telephone will not automatically respond to the IR signal and connect the call line. In other words, the inconvenience of not ringing in response to an IR signal can be prevented. In this case, an on-hook telephone can be connected to the analog telephone network and supplied with an IR signal to ring in response to an incoming call. This ensures that the caller is notified of a reverse call, allowing them to respond. When the on-hook telephone is taken off-hook, the call line is connected and a voice call with a person at the emergency call receiving agency 5 becomes possible.

[Summary of operation of emergency notification device 1]
Fig. 6 is a flowchart for explaining the details of the processing performed in the emergency call device 1 of the embodiment. The processing of the flowchart shown in Fig. 6 is processing that is mainly performed by the switching control unit 222 of the line connection control unit 1022 of the telephone control unit 102. That is, when the call button 104 is pressed, the call control unit 1013 functions to send an emergency call to the emergency call receiving agency 5 and then transmits a disconnection signal, and then the processing of the flowchart shown in Fig. 6 is performed by the switching control unit 222.

The switching control unit 222 determines whether an IR signal (reverse call signal) has arrived based on the detection output from the reverse call detection unit 1012 (step S101). If it is determined in the determination process of step S101 that an IR signal has not arrived, the process from step S101 is repeated. Assume that it is determined in the determination process of step S101 that an IR signal has arrived. In this case, the switching control unit 222 determines whether either the dedicated telephone 2 or the general telephone 3 connected to the switching control unit 222 is off-hook (in an off-hook state) based on the detection output from the line monitoring unit 1011 (step S102).

Let us assume that in the determination process of step S102, it is determined that either the dedicated telephone 2 or the general telephone 3 is off the hook. In this case, the switching control unit 222 controls the switching unit 221 based on the detection output from the hook state detection unit 1021 to disconnect the off-hook telephone from the holding line, i.e., the analog telephone network 4 (step S103). Note that the processes of steps S101 to S103 are executed immediately if it is determined in step S101 that an IR signal has arrived. Therefore, it is possible to reliably prevent the off-hook telephone from transmitting a response signal in response to the IR signal.

After the processing of step S103, or if it is determined in the determination processing of step S102 that there are no off-hook telephones, the processing of step S104 is performed. That is, based on the detection output from the hook state detection unit 1021, the switching control unit 222 controls the switching unit 221 to connect on-hook telephones to the holding line, i.e., the analog telephone network 4 (step S104). As a result, an IR signal is supplied to the on-hook telephone, and in response, an incoming call ringing (ringtone) begins.

Then, the telephone that is ringing while on-hook waits until it is taken off-hook (step S105). The handset of the telephone that is ringing while on-hook is then picked up and goes off-hook. In this case, a response signal is sent from the telephone to the emergency call receiving agency 5 via the analog telephone network 4, and the call line is connected (step S106). That is, a call line is connected between the telephone that has gone from ringing while on-hook to off-hook and the emergency call receiving agency 5 via the analog telephone network 4, enabling a call (reverse call). The switching control unit 222 then determines, based on the detection output from the hook state detection unit 1021, whether the telephone that went from ringing while on-hook to off-hook has gone on-hook (step S107).

If it is determined in the determination process of step S107 that the telephone has not returned to the on-hook state, the process from step S107 is repeated. Assume that it is determined in the determination process of step S107 that the telephone has returned to the on-hook state. In this case, a disconnection signal is transmitted from the telephone that has returned to the on-hook state, and the switching control unit 222 then controls the switching unit 221 to disconnect the telephone that was connected to the call line from the analog telephone network 4 (step S108). This ends the process of the flowchart shown in Figure 6.

[Effects of the embodiment]
In the case of the emergency call device 1 of this embodiment, even if an emergency call is made when one of the dedicated telephone 2 and the general telephone 3 connected to the device is off-hook, the off-hook telephone will not automatically respond to the IR signal (back call signal). Instead, the other on-hook telephone rings to notify the caller of the back call. This allows the caller to take the on-hook telephone off-hook and reliably respond to the back call from the emergency call receiving agency 5.

[Modification]
In the above-described embodiment, an example has been described in which two telephones, a dedicated telephone 2 and a general telephone 3, are connected to the emergency notification device 1. However, this is not limited to this. The present invention can be applied to cases in which multiple dedicated telephones or multiple general telephones are connected to the emergency notification device 1. In short, when an IR signal arrives after an emergency notification, the telephones that are off-hook are disconnected from the analog telephone network 4, and the telephones that are on-hook are connected to the analog telephone network, so that they can ring in response to the IR signal. As a result, the telephone that rings can be used to connect a call line to the emergency notification receiving agency 5 and make a voice call.

Furthermore, if the dedicated telephone 2 is off-hook after an emergency call is made, considering that dedicated telephones are only used for emergency calls, there is a possibility that the caller has picked up the handset of the dedicated telephone and is waiting for a return call. Therefore, if the dedicated telephone is off-hook after an emergency call is made, rather than supplying an IR signal to an on-hook telephone to ring, the dedicated telephone may be controlled to automatically answer the IR signal and connect the call line. Because the hook state detection unit 1021 can detect the hook state of the connected telephone, the switching control unit 222 can distinguish whether the off-hook telephone is a dedicated telephone or a general telephone and perform switching control accordingly.

[others]
As can be seen from the above description of the embodiment, the function of the claimed reverse call detection means is realized by the reverse call detection unit 1012 of the emergency notification device 1 of the embodiment, and the function of the claimed line monitoring means is realized by the line monitoring unit 1011 of the emergency notification device 1 of the embodiment. Also, the function of the claimed hook state detection means is realized by the hook state detection unit 1021 of the emergency notification device 1 of the embodiment, and the function of the claimed switching means is realized by the switching unit 221 of the emergency notification device 1 of the embodiment. Also, the function of the claimed control means is realized by the switching control unit 222 of the emergency notification device 1 of the embodiment.

The method corresponding to the processing of the flowchart shown in Figure 6 is an embodiment of the callback response control method of the present invention. Furthermore, the functions of the line monitoring unit 1011, callback detection unit 1012, notification control unit 1013, hook state detection unit 1021, switching control unit 222, and switching unit 221 shown in Figure 2 can also be realized by software as functions of the CPU unit 103 through a program executed in the CPU unit 103, which is connected to the analog telephone network 4, dedicated telephone 2, and general telephone 3 and sends and receives signals therebetween. Therefore, the program that performs the processing of the flowchart shown in Figure 6 is an embodiment of the callback response control program of the present invention.

1...Emergency call device, 101...Line control unit, 1011...Line monitoring unit, 1012...Back call detection unit, 1013...Call control unit, 102...Telephone control unit, 1021...Hook state detection unit, 1022...Line connection control unit, 221...Switching unit, 222...Switching control unit, 103...CPU unit, 104...Call button, 2...Dedicated telephone, 3...General telephone, 4...Analog telephone network, 5...Emergency call receiving agency, 6...External telephone

Claims (4)

An emergency call device to which a plurality of telephones for making calls to an emergency call receiving agency are connected, and which makes an emergency call to the emergency call receiving agency through an analog telephone network,
a call detection means for detecting the arrival of a call signal from the analog telephone network after an emergency call is made;
a line monitoring means for monitoring signals from the analog telephone network and detecting whether or not a telephone is off the hook among the plurality of telephones connected to the line monitoring means;
a hook state detection means for detecting the hook state of each of the plurality of telephone sets connected to the own device;
a switching means for switching between connection and non-connection to the analog telephone network for each of the plurality of telephones connected to the own device;
and control means for controlling said switching means so that, when said reverse call detection means detects the arrival of the call signal and said line monitoring means detects the presence of a telephone set in an off-hook state, said switching means disconnects the off-hook telephone set from said analog telephone network and connects the on-hook telephone set to said analog telephone network based on the detection output of said hook state detection means. The emergency call device according to claim 1,
The plurality of telephones are dedicated telephones that only make call-back calls in response to call-backs from the emergency call receiving agency, and general telephones that can make outside calls or internal calls,
The emergency call device is characterized in that the control means controls the switching means so that, when the general telephone is in an off-hook state and the dedicated telephone is in an on-hook state, the general telephone is disconnected from the telephone line and the dedicated telephone is connected to the telephone line. The emergency call device according to claim 1,
The emergency call device is characterized in that the line monitoring means detects that there is a telephone set that is off the hook when it receives a 30-second dial tone, then a 60-second busy tone, and power supply from the analog telephone network is stopped. The emergency call device according to claim 1,
The emergency call device is characterized in that the line monitoring means detects that there is a telephone set that is off the hook when a dial tone or a busy tone is received.