JP7611316B2 - Fire alarm system - Google Patents

Description

The present invention relates to a fire alarm system that uses a transmission line that connects a fire detector from a receiver and a telephone line to connect a telephone master and a telephone handset.

Conventionally, in fire alarm systems known as R-type, a terminal device with a transmission function, such as a fire detector, is connected to a transmission line drawn from a receiver, and when a fire is detected, for example based on a fire interrupt from the fire detector, a search command is issued to identify the address of the fire detector that triggered the alarm, the fire address is displayed, and fire data is collected from the identified fire detector for monitoring.

In this way, knowing the address of the fire detector that detected the fire makes it possible to provide appropriate evacuation guidance and engage in fire-fighting activities, making this a vital function, especially for fire monitoring in large-scale facilities.

In addition, in fire alarm systems, a telephone base unit is installed in the receiver as an emergency communication device, and a telephone jack installed in the transmitter, etc. is connected to a telephone line that is pulled out from the receiver to the alert area. In the event of a fire or inspection, when a maintenance telephone handset carried by a person in charge is connected to the telephone jack of the transmitter, etc., a call is made on the receiver, and a call connection with the maintenance telephone handset can be established by off-hooking the telephone base unit.

In addition, emergency telephone equipment may also be installed as an associated facility for the fire alarm system. The emergency telephone equipment consists of an emergency telephone board with a telephone master unit installed in the same place as the receiver, and telephone and control lines are drawn from the emergency telephone board to the alert area, where the emergency telephone handset is connected.

The maintenance telephone equipment for fire alarm systems cannot be called by specifying a maintenance telephone handset from the main telephone unit, but the emergency telephone equipment can be called by specifying an emergency telephone handset of your choice by calling a telephone number from the emergency telephone board, and can be used not only in emergencies such as fires, but also for daily telephone contact to maintain and manage the equipment.

JP 2004-064709 A JP 2017-004451 A JP 2016-076064 A JP 2017-068523 A Japanese Patent Application Publication No. 10-69591

However, conventional emergency telephone equipment that can call a specific handset must be installed as part of the fire alarm system, which increases the cost of the equipment. On the other hand, maintenance telephone equipment for fire alarm systems, which connects a maintenance handset to a telephone jack on a telephone line and then connects to a master telephone unit, requires less equipment cost, but does not allow for advanced call control such as calling a specific handset, and is less convenient than emergency telephone equipment.

The present invention aims to provide a fire alarm system that has a highly convenient calling function that allows for calls by connecting a telephone handset to a telephone jack in addition to advanced call control, including calling a specific telephone handset using the transmission function used in R-type fire alarm systems.

(Fire alarm system)
The present invention is a fire alarm system in which a terminal device including a telephone repeater is connected to a transmission line drawn from a receiver to a security zone, and the telephone repeater is connected to a telephone line also drawn from the receiver to the security zone and connected to a telephone jack,
The receiver is
A call connection is possible between a first handset connected to a telephone line via a telephone repeater and a second handset connected to the telephone line via a telephone jack,
A call connection with the first handset is controlled by transmitting and receiving a predetermined call control signal via a transmission line between the first handset and a telephone repeater to which the first handset is connected ;
A call connection with the second handset is controlled based on a connection state of the second handset to a telephone jack;
When a connection to a telephone jack of a second telephone handset is detected during a call connection with a first telephone handset, the call connection is switched to the second telephone handset.

(Hold tone on first handset)
When the receiver detects a connection of a second telephone handset to a telephone jack during a call connection with a first telephone handset and switches to a call connection with the second telephone handset, the receiver transmits a hold command signal via a transmission line to a telephone relay section connected to the first telephone handset that was previously connected to the call, causing a hold sound to be output from the first telephone handset that was previously connected to the call.

(Fire alarm system with first and second telephone facilities)
In another embodiment of the present invention, a transmission line is drawn from the receiver to the security area and connected to terminal equipment including a telephone repeater;
a first telephone line extending from the receiver to the security zone and connected to a telephone repeater;
a second telephone line extending from the receiver into the security zone and connected to a telephone jack;
A fire alarm system provided with :
The receiver is
storing address information capable of identifying the telephone repeater;
A telephone call connection is possible between a first telephone handset connected to a first telephone line via a telephone repeater and a second telephone handset connected to a second telephone line via a telephone jack,
A call connection with the first handset is controlled by transmitting and receiving a predetermined call control signal via a transmission line between the first handset and a telephone repeater to which the first handset is connected ;
A call connection with the second handset is controlled based on a connection state of the second handset to a telephone jack ;
When an incoming call is received from a first handset, a display is displayed indicating that an incoming call has been received so as to identify the first handset that is the call source based on address information of a telephone repeater to which the first handset is connected;
When an incoming call is received from the second handset, a display is given to indicate that an incoming call is received from the second handset .

(Effectiveness of fire alarm systems)
The present invention is a fire alarm system in which a terminal device including a telephone repeater is connected to a transmission line drawn from a receiver into a security zone, and the telephone repeater is connected to a telephone line also drawn from the receiver into the security zone and to which a telephone jack is connected, and the receiver is capable of making a call connection with a first telephone handset connected to the telephone line via the telephone repeater, and a second telephone handset connected to the telephone line via a telephone jack, and the call connection with the first telephone handset is controlled by sending and receiving a predetermined call control signal via the transmission line between the telephone repeater to which the first telephone handset is connected , and the call connection with the second telephone handset is controlled by the connection status of the second telephone handset to the telephone jack, and if a connection of the second telephone handset to a telephone jack is detected during a call connection with the first telephone handset, the call connection with the second telephone handset is switched to. Therefore, by utilizing the transmission function of the transmission line used in an R-type fire alarm system for call control, advanced call control including calling designated the first telephone handset can be realized simply and at low cost.

In addition to advanced call control, including calling a specific first telephone handset using a transmission line, it is also possible to make calls by connecting a second telephone handset to a telephone jack without compromising the functionality, providing even greater convenience.

In addition, when a second handset is connected to the telephone jack while a call is in progress between the base unit and the first handset, the previous call connection between the base unit and the first handset is put on hold and the call with the second handset takes priority.

(Effectiveness of fire alarm systems equipped with emergency telephone equipment and maintenance telephone equipment)
In another aspect of the present invention, there is provided a fire alarm system including a transmission line drawn from a receiver to a security zone and connected to a terminal device including a telephone repeater, a first telephone line drawn from the receiver to the security zone and connected to the telephone repeater, and a second telephone line drawn from the receiver to the security zone and connected to a telephone jack, in which the receiver stores address information for identifying the telephone repeater, and is capable of connecting to a first telephone handset connected to the first telephone line via the telephone repeater and a second telephone handset connected to the second telephone line via the telephone jack, the connection to the first telephone handset is controlled by sending and receiving a predetermined call control signal via the transmission line between the receiver and the telephone repeater to which the first telephone handset is connected, and the connection to the second telephone handset is controlled by sending and receiving a predetermined call control signal via the transmission line between the receiver and the telephone repeater to which the first telephone handset is connected, is controlled by the connection status of the second telephone handset to the telephone jack , and when a call is received from the first telephone handset, a display is displayed indicating that there has been an incoming call so that the first telephone handset that is the source of the call can be identified based on the address information of the telephone repeater to which the first telephone handset is connected, and when a call is received from the second telephone handset, a display is displayed indicating that the call is received from the second telephone handset.As a result, with the first telephone equipment using the first telephone line, calls can be made by sending and receiving a specified call control signal via the transmission line , and with the second telephone equipment using the second telephone line, calls can be made by connecting the second telephone handset to the telephone jack, making it possible to use both the first telephone equipment and the second telephone equipment, further improving convenience.

In addition, by integrating the functions of the base unit devices for the first and second telephone equipment into the receiver, the installation space for the fire alarm equipment and telephone equipment is reduced, and furthermore, calls with the first telephone handset or the second telephone handset can be made using the same base unit, making call operations simple and easy without having to change locations.

FIG. 1 is an explanatory diagram showing an embodiment of a fire alarm system having a call control function. FIG. 2 is a block diagram illustrating an embodiment of the telephone repeater of FIG. FIG. 2 is a block diagram showing an embodiment of a telephone base unit circuit section and a call detection circuit section provided in the receiver of FIG. 1; A time chart showing call control in which a telephone base unit calls a specific telephone handset. A time chart showing call control with the base unit when the handset is off-hook A time chart showing call control when a handset goes off-hook while the base unit is in a call with another handset A time chart showing call control when a call is received from another handset during a call between the base unit and the handset and the call is switched over. A time chart showing call control for a three-way call using a telephone base unit and two telephone handsets. A time chart showing call control performed by connecting a maintenance telephone handset to a telephone jack. An explanatory diagram showing an embodiment of a fire alarm system equipped with a call control function for emergency telephone equipment linked to an emergency broadcasting system and a maintenance telephone equipment used for maintenance and inspection.

[Fire alarm system]
(Outline of fire alarm system with call control function)
Fig. 1 is an explanatory diagram showing the outline of a fire alarm system equipped with a call control function. As shown in Fig. 1, a receiver 10, for example, of type R, is installed in a manager's room on the first floor of a building in which the fire alarm system is installed, and transmission lines 12a, 12b and telephone lines 16a, 16b are drawn out from the receiver 10 to the alert area.

A number of fire detectors 14 and repeaters 15 with transmission functions and unique addresses are connected to the transmission lines 12a and 12b. A number of telephone repeaters 18 with telephone handsets 20 are connected to the transmission lines 12a and 12b and the telephone lines 16a and 16b, and the telephone repeaters 18 are set with unique addresses and have transmission functions and call control functions. A telephone base unit 28 is provided in the receiver 10 in correspondence with the telephone handsets 20. The telephone lines 16a and 16b ensure the transmission quality of audio signals in the audio frequency band of 300 to 3400H in the audible band.

Here, the maximum number of addresses set for the fire detectors 14, repeaters 15, and telephone repeaters 18 connected to the transmission lines 12a and 12b is, for example, 255, and a maximum of 255 terminal devices including fire detectors 14, repeaters 15, and telephone repeaters 18 can be connected to the transmission lines 12a and 12b.

A transmitter 36 is connected to the repeater 15. The transmitter 36 is provided with a transmitter button 36a. When the transmitter button 36a is pressed to turn on in the event of a fire, a transmission signal is output to the repeater 15, and a fire notification signal is sent from the repeater 15 to the receiver 10 via the transmission lines 12a and 12b, and a fire alarm is output.

The transmitter 36 is also provided with a telephone jack 38, which is connected to the telephone lines 16a and 16b. When the maintenance telephone handset 40 carried by the person in charge is plugged into the telephone jack 38, the maintenance telephone handset 40 is connected to the telephone lines 16a and 16b, and a call connection with the telephone base unit 28 provided in the receiver 10 is established, allowing a call to be made.

(Receiver functional configuration)
The receiver 10 comprises a receiving control unit 22, a transmission unit 24, a telephone base unit circuit unit 26, a telephone base unit 28, a display 30 with a touch panel, a display unit 31, an operation unit 32, an alarm unit 33 with a speaker, a notification unit 34 and a call detection circuit unit 35.

The reception control unit 22 is a computer circuit equipped with a CPU, memory, various input/output ports, etc. The transmission unit 24 transmits and receives signals according to a predetermined communication protocol between the fire detector 14, the repeater 15, or the telephone repeater 18 connected to the transmission lines 12a and 12b.

Downstream signals from the transmission unit 24 to the fire detector 14, repeater 15, or telephone repeater 18 are transmitted in voltage mode. This voltage mode signal is transmitted as a voltage pulse that changes the line voltage of the transmission lines 12a and 12b between, for example, 18 volts and 30 volts.

In contrast, the upstream signal from the fire detector 14, repeater 15, or telephone repeater 18 to the receiver 10 is transmitted in current mode. In this current mode, a signal current is passed through the transmission lines 12a and 12b at the timing of bit 1 of the transmission data, and the upstream signal is transmitted to the receiver as a so-called current pulse train.

(Fire Monitoring and Control Department)
The reception control unit 22 of the receiver 10 is provided with the function of a fire monitoring control unit 44 as a function realized by the execution of a program by the CPU.

During normal monitoring, the fire monitoring control unit 44 periodically instructs the transmission unit 24 to transmit a broadcast batch AD conversion signal including a batch AD conversion command. The fire detector 14 that receives this batch AD conversion signal detects and stores the smoke concentration or temperature as sensor data, and the repeater 15 detects and stores the transmitter signal at that time. The fire monitoring control unit 44 then transmits a call signal including a polling command that sequentially specifies the terminal addresses.

When the fire detector 14 receives a call signal with an address that matches its own address, it transmits a response signal including the sensor data it is holding at that time to the receiver 10. In addition, when the fire detector 14 detects a fire, it transmits a fire interrupt signal to the receiver 10.

When the repeater 15 receives a call signal with an address that matches its own address, it transmits a response signal including the transmitter signal it is holding at that time to the receiver 10. In addition, when the repeater 15 receives a transmitter signal that is turned on by pressing the transmitter button 36a of the transmitter 36, it transmits a fire interrupt signal to the receiver 10 as a fire notification signal, in the same way as the fire detector 14.

When the fire monitoring control unit 44 receives a fire interrupt signal via the transmission unit 24, it transmits a group search command signal to identify the group including the fire detector 14 and repeater 15 that have detected the fire, then transmits an intra-group search command signal to identify the address of the fire detector 14 or repeater 15 that has detected the fire, outputs a fire alarm and displays the fire occurrence address or transmitter address, and then controls the collection and monitoring of fire data from the identified fire detector 14 or repeater 15.

(Telephone base unit control unit)
The reception control unit 22 of the receiver 10 is provided with the function of a telephone base unit control unit 46 as a function realized by the execution of a program by the CPU.

The telephone base unit control unit 46 instructs the transmission unit 24 to transmit and receive command signals required for various call controls between the telephone repeater 18 and the telephone base unit 28 via the transmission lines 12a and 12b, and controls call connection and call cut (disconnection) between the telephone base unit 28 and the telephone handset 20 via the telephone lines 16a and 16b.

The telephone base unit control unit 46 of this embodiment performs the following call control.
(1) Call control by calling a specific telephone handset.
(2) Call control by calling from a telephone handset.
(3) Call switching control when a call is received from another handset while a call is being made with another handset.
(4) Three-way call control using a telephone base unit and two telephone handsets.
(5) Call control by connecting a maintenance telephone handset to a telephone jack.

Of these, in the call controls (1) to (4), command signals such as a call command signal, an incoming call response command signal, a hold command signal, and a busy command signal are used. The call command signal is a signal that requests the telephone handset to make a call. The incoming call response command signal is a signal that is sent when the telephone handset goes off-hook upon receiving a call command signal. The hold command signal is a signal that instructs the telephone handset to output a hold tone. The busy command signal is a signal that instructs the telephone handset to output a busy tone. Details of communication control using such command signals will be made clear later.

(Call detection circuit section)
The call detection circuit unit 35 provided in the receiver 10 detects a line current that flows when the plug 42 of the maintenance telephone handset 40 is inserted into the telephone jack 38 of the transmitter 36 and connected to the telephone lines 16a, 16b, and outputs a call detection signal to the receiving control unit 22.

When the telephone base unit control unit 46 provided in the reception control unit 22 receives a call detection signal from the call detection circuit unit 35, it outputs a ring tone from the speaker of the alarm unit 33 based on the call connection of the maintenance telephone handset 40. When the person in charge hears this and picks up the telephone base unit 28, the telephone base unit 28 is connected to the telephone lines 16a and 16b by the telephone base unit circuit unit 26 based on the detection of the telephone base unit 28 being off-hook, and a call connection with the maintenance telephone handset 40 is established.

[Configuration of telephone repeater]
Fig. 2 is a block diagram showing an embodiment of the telephone repeater of Fig. 1. As shown in Fig. 2, the circuit section of the telephone repeater 18 is provided with a telephone handset control section 48 and a transmission section 50 as the circuit section on the transmission lines 12a and 12b side, and is provided with a connection switching section 52, a control sound generating section 54, a pair of switch circuits 56, a transformer 58, a hook switch 60, and a speaker 61 as the circuit section on the telephone lines 16a and 16b side, and the telephone handset 20 is provided with a handset 45 and a handset 47.

The telephone handset control unit 48 is composed of a computer circuit equipped with a CPU, memory, various input/output ports, etc., and the functions of the telephone handset control unit 48 are realized by the execution of a program by the CPU.

The telephone handset control unit 48 of this embodiment controls the following calls.
(1) Call control by calling the telephone base unit.
(2) Call control by calls from the telephone base unit.
(3) Call switching control by calling the base unit during a call with another handset.
(4) Three-way call control using a telephone base unit and two telephone handsets.

In these call controls, command signals such as a call command signal, an incoming call response command signal, a hold command signal, and a call in progress command signal are used, and details of the call controls will be explained later.

The transmission unit 50 transmits and receives various command signals necessary for call control between the transmission unit 24 of the receiver 10 shown in FIG. 1 via the transmission lines 12a and 12b in accordance with the same communication protocol as in the case of fire monitoring. In addition, the transmission unit 50 receives downstream signals from the receiver 10 in voltage mode, and transmits upstream signals to the receiver 10 in current mode.

The connection switching unit 52 operates according to instructions from the telephone handset control unit 48 to turn on and off the switch circuit unit 56, which uses relay contacts, semiconductor switch elements, etc., and connects and disconnects the telephone handset 20 to and from the telephone lines 16a and 16b.

The control sound generating unit 54 operates according to instructions from the telephone handset control unit 48, generating audio signals such as a predetermined line connection sound, a ring tone for the telephone base unit, a hold tone, a busy tone, etc., and outputs them to the transmitter 47 of the telephone handset 20. It also generates an audio signal for a ring tone in response to a call from the telephone base unit and outputs it to the speaker 61.

The transformer 58 connects its primary winding to the telephone lines 16a and 16b, and its secondary winding to the handset 45. It picks up and amplifies only the AC audio signals from the telephone lines 16a and 16b, on which a predetermined DC voltage is superimposed, and also prevents feedback. The transmitter 47 of the telephone handset 20 is connected to the telephone lines 16a and 16b.

The hook switch 60 detects whether the telephone handset 20 is off-hook or on-hook and outputs an off-hook detection signal or an on-hook detection signal to the telephone handset control unit 48.

The telephone circuit on the telephone lines 16a and 16b in FIG. 2 shows a basic analog telephone circuit, but is not limited to this. An audio amplifier may be provided as necessary, and the circuit may be a digital telephone circuit that receives digital audio signals, converts them from digital to analog, outputs them to the handset 45, and converts the audio signals from the transmitter 47 into digital signals and transmits them.

[Configuration of the telephone base unit circuit section and the call detection circuit section of the receiver]
FIG. 3 is a block diagram showing an embodiment of a telephone base unit circuit section and a call detection circuit section provided in the receiver of FIG.

(Telephone base unit circuit section)
3, the telephone base unit circuit section 26 is provided with a connection switching section 62, a control sound generating section 64, a pair of switch circuits 66, a transformer 68, and a hook switch 70, and the telephone base unit 28 is provided with a handset 72 and a transmitter 74. A telephone line voltage Vt of, for example, DC 48 V is applied from the telephone base unit circuit section 26 between the telephone lines 16a and 16b.

The connection switching unit 62 operates according to instructions from the telephone base unit control unit 46 in FIG. 1 to turn on and off the switch circuit unit 66, thereby connecting and disconnecting the telephone base unit 28 to and from the telephone lines 16a and 16b.

The control sound generating unit 64 operates according to instructions from the telephone base unit control unit 46, generates audio signals such as a predetermined line connection sound, a ring tone indicating a call to the telephone handset 20, a hold tone, a busy tone, etc., and outputs them to the handset 72 of the telephone base unit 28. It also generates an audio signal of a ring tone in response to a call from the telephone handset 20 or the maintenance telephone handset 40, and outputs it to a speaker provided in the alarm unit 33, for example.

The transformer 68 connects its primary winding to the telephone lines 16a and 16b, and its secondary winding to a handset 72. Only the AC audio signals from the telephone lines 16a and 16b, on which a predetermined telephone line voltage Vt is superimposed, are sent to the handset 72 and amplified, and howling is prevented. The transmitter 74 of the telephone base unit 28 is connected to the telephone lines 16a and 16b.

The hook switch 70 detects whether the telephone base unit 28 is off-hook or on-hook and outputs an off-hook detection signal or an on-hook detection signal to the telephone base unit control unit 46.

The telephone circuit on the telephone lines 16a and 16b in FIG. 3 shows a basic analog telephone circuit, similar to the telephone repeater 18 in FIG. 2, but is not limited to this and may include an audio amplifier as necessary, or may be a digital telephone circuit.

(Call detection circuit section)
As shown in FIG. 3, in the call detection circuit unit 35, resistors 76, 78, and 80 are connected in series between the telephone line 16a, to which a predetermined line voltage Vt is applied, and the negative telephone line 16b, with the telephone line 16a being drawn out to the terminal side from between resistors 76 and 78, and a call detection signal being taken out from between resistors 78 and 80 and output to the receiving control unit 22.

As shown in FIG. 1, when the plug 42 of the maintenance telephone handset 40 is inserted into the telephone jack 38 of the transmitter 36 and the maintenance telephone handset 40 is connected between the telephone lines 16a and 16b, the maintenance telephone handset 40 also has a telephone circuit equipped with a transformer, handset, and transmitter, the same as the telephone handset 20 shown in FIG. 2 or the telephone base unit 28 shown in FIG. 3, and the transmitter is connected between the telephone lines 16a and 16b via the transformer primary winding, causing a predetermined line current to flow.

The line current associated with connecting this maintenance telephone 40 to the telephone jack 38 flows through resistor 76 of the call detection circuit unit 35 shown in Figure 3 to the telephone line 16a, and the line voltage drops by the voltage drop of resistor 76, and the detection voltage output as the call detection signal divided by resistors 78 and 80 also drops. The telephone base unit control unit 46 of the receiving control unit 22 determines that the maintenance telephone handset 40 is connected based on the drop in the level of the call detection signal, and outputs a ring tone and displays a screen indicating that the maintenance telephone handset 40 is being called.

[Call control between the telephone base unit and the telephone handset]
(Designated call to a handset by a base unit)
FIG. 4 is a time chart showing call control in which the telephone base unit calls a specific telephone handset, and the control operation is performed by the telephone base unit control unit 46 of the receiver 10 shown in FIG. 1 and the telephone handset control unit 48 of the telephone repeater 18 shown in FIG. 2.

When the person in charge picks up the telephone base unit 28 to contact another person in the security zone, an off-hook detection signal is output from the hook switch 70, and as shown in FIG. 4, the telephone base unit control unit 46 determines in step S1 that the telephone base unit 28 is off-hook and proceeds to step S2, where it displays a handset call screen on the display 30, and at the same time instructs the control sound generation unit 64 to output a line connection sound, such as a continuous tone such as "beep," from the handset 72 of the telephone base unit 28.

The handset call screen displayed on the display 30 in step S2 displays key buttons arranged as 0, 1-9, #, and *. When a handset call operation is performed by touching the telephone number of the telephone handset to be called, the telephone base unit control unit 46 recognizes the handset call operation in step S3 and proceeds to step S4, where it instructs the transmission unit 24 to send a call command signal specifying the repeater address corresponding to the called telephone number to the transmission lines 12a and 12b. At this time, a ring tone is output from the telephone base unit 28 to the telephone handset.

When the telephone handset control unit 48 of the telephone repeater 18 receives a call command signal specifying its own address from the transmission unit 50 via the transmission lines 12a and 12b, in step S5 it instructs the control sound generation unit 54 to make a call by outputting a ring tone from the speaker 61.

When the person at the site picks up the handset 20 in response to this call, the off-hook state is determined in step S6 by an off-hook detection signal from the hook switch 60, and in step S7 the transmission unit 50 is instructed to send a call response command signal including the receiver's address to the receiver 10 via the transmission lines 12a and 12b. Next, in step S8 the connection switching unit 52 is instructed to turn on the switch circuit unit 56, and a call connection is made that connects the telephone circuit unit on the handset 20 side to the telephone lines 16a and 16b.

When the telephone base unit control unit 46 of the receiver 10 receives the incoming call response command signal sent from the telephone repeater 18 in step S7, it stops outputting the ring tone to the telephone handset 20, and in step S9 instructs the connection switching unit 62 to turn on the switch circuit unit 66, and makes a call connection that connects the telephone base unit circuit unit 26 of the telephone base unit 28 to the telephone lines 16a and 16b.

As a result, the telephone base unit 28 and the called telephone handset 20 are connected to the telephone lines 16a and 16b, and a call can be made. When the call ends, the telephone base unit 28 and the telephone handset 20 are returned, and the on-hook state is determined in step S10 or S12, and the call is disconnected from the telephone lines 16a and 16b in step S11 or S13, and the call ends.

(Calling the base unit by a handset)
Fig. 5 is a time chart showing the call control for calling the base station by the handset. When a person in the security area picks up the handset 20 to contact the receiver 10, an off-hook detection signal is output from the hook switch 60. As shown in Fig. 5, the handset control unit 48 determines in step S21 that the handset 20 is off-hook, and proceeds to step S22 to instruct the control sound generation unit 54 to output a line connection sound, which is a continuous sound such as "beep", from the receiver 45 of the handset 20.

Then, in step S23, the telephone handset control unit 48 instructs the transmission unit 50 to transmit a call command signal including its own address to the receiver 10 via the transmission lines 12a and 12b. At this time, the telephone handset 20 outputs a ring tone to the telephone base unit 28.

When the telephone base unit control unit 46 of the receiver 10 receives a call command signal including the repeater address from the transmission unit 50 via the transmission lines 12a and 12b, in step S24 it instructs the alarm unit 33 to output a ring tone from the speaker to make a call, and then proceeds to step S25 to display a handset call screen on the display 30 to display the telephone number of the handset being called, etc.

When the person in charge picks up the telephone base unit 28 installed on the receiver 10 in response to the ring tone in step S24, the telephone base unit control unit 46 determines in step S26 that the telephone base unit 28 is off-hook, instructs the transmission unit 24 in step S27 to send a call response command signal specifying the repeater address that made the call to the transmission lines 12a, 12b, and instructs the connection switching unit 62 in step S28 to turn on the switch circuit unit 66, thereby connecting the telephone base unit 28 to the telephone lines 16a, 16b for communication.

On the other hand, when the telephone handset control unit 48 receives the call response command signal specifying its own address transmitted from the receiver 10 in step S27, it stops the ring tone to the telephone base unit 28 and proceeds to step S29, where it instructs the connection switching unit 52 to turn on the switch circuit unit 56, thereby connecting the telephone handset 20 to the telephone lines 16a and 16b.

As a result, the telephone handset 20 and the called telephone base unit 28 are connected to the telephone lines 16a and 16b, and the call can be made. When the call ends, the telephone handset 20 and the telephone base unit 28 are returned, and the on-hook state is determined in step S30 or S32, and the call is disconnected from the telephone lines 16a and 16b in step S31 or S33, and the call connection is terminated.

(Calling a handset when the base unit is busy)
FIG. 6 is a time chart showing call control when a handset goes off-hook during a call between the base unit and another handset.

Assuming that during a call from the telephone base unit shown in FIG. 4 or a call from the telephone handset shown in FIG. 5, as shown in FIG. 6, the telephone handset control unit 48 of another telephone repeater 18 determines in step S41 that the telephone handset 20 is off-hook, outputs a line connection sound from the telephone handset 20 in step S42, and then transmits a call command signal including its own address to the receiver 10 via the transmission lines 12a and 12b in step S43, causing the speaker of the alarm unit 33 to output a ring tone.

In this case, the telephone base unit control unit 46 of the receiver 10 receives the call command signal sent from the telephone repeater 18 in step S43, but determines in step S44 that a call is in progress with another telephone handset, and in step S45 displays a new handset call on the handset call screen on the display 30. Then, in step S46, it transmits a busy command signal specifying the address of the telephone repeater 18 that sent the call command signal to the transmission lines 12a, 12b.

When the telephone handset control unit 48 of the telephone repeater 18 receives a call-in-progress command signal specifying its own address via the transmission lines 12a and 12b, in step S47 it instructs the control sound generation unit 54 to output a specified call-in-progress sound from the handset 45 of the telephone handset 20.

As a result, the person who picked up the telephone handset 20 learns that the telephone base unit 28 is busy with a call and returns the telephone handset 20 to its original position, and the telephone handset control unit 48 determines that the handset is on-hook in step S48 and terminates the call connection.

(Call switching due to a call from another handset during a call between the base unit and handset)
7 is a time chart showing call control when a call is received from another handset during a call between the base unit and the handset, and the call is switched over. Here, the telephone repeater 18 that made the first call is called the telephone repeater 18-1, the telephone repeater 18 that made the second call is called the telephone repeater 18-2, the telephone handset control units 48 provided in each are called the telephone handset control units 48-1 and 48-2, and the telephone handset 20 is called the telephone handset 20-1 and 20-2.

As shown in Figure 7, a call is made from the telephone handset control unit 48-1 of the telephone repeater 18-1, and a call connection is established between the telephone base unit 28 and the telephone handset 20-1 through call control between the telephone base unit control unit 46 of the receiver 10. In this case, the call control of steps S51 to S59 is the same as steps S21 to S29 in Figure 5, so a description thereof will be omitted.

Next, when the telephone handset control unit 48-2 of another telephone repeater 18-2 determines in step S60 that the telephone handset 20-2 is off-hook, a line connection sound is output from the telephone handset 20-2, and then in step S61, the telephone base unit 28 transmits a call command signal including its own address via the transmission lines 12a and 12b to the receiver 10 that is currently in a call.

When the telephone base unit control unit 46 of the receiver 10 receives the call command signal transmitted from the telephone repeater 18-2, in step S62, it displays the call to the telephone handset 20-2 on the display 30 and also outputs a predetermined warning sound from the speaker of the alarm unit 33.

As a result, when the person on the call realizes that there is a call from another telephone handset 20-2 and performs an operation to select it, the telephone base unit control unit 46 recognizes the selection operation of the other telephone handset 20-2 in step S63 and proceeds to step S64, where it sends a call response command signal specifying the address of the telephone repeater 18-2 to the transmission lines 12a and 12b, which is received by the telephone repeater 18-2, and the telephone handset control unit 48-2 connects the telephone handset 20-2 to the telephone lines 16a and 16b in step S65.

In addition, in step S66, the telephone base unit control unit 46 transmits a hold command signal specifying the address of the telephone repeater 18-1 of the telephone handset 20-1 that was in a call up until that point to the transmission lines 12a, 12b. This is received by the telephone repeater 18-1, and in step S67, the telephone handset control unit 48-1 disconnects the call by disconnecting the telephone handset 20-1 from the telephone lines 16a, 16b, and causes the telephone handset 20-1 to output a specified hold tone.

After that, when the call between the telephone base unit 28 and the telephone handset 20-2 ends and the telephone handset control unit 48-2 determines that the telephone handset is on-hook in step S68, the process proceeds to step S69, where a call end command signal including the telephone handset's own address is sent to the transmission lines 12a and 12b.

When the telephone base unit control unit 46 determines that it has received a call end command signal from the telephone repeater 18-2, it sends a hold release command signal specifying the address of the telephone repeater 18-1 that is on hold to the transmission lines 12a and 12b in step S70. When the telephone handset control unit 48-1 receives a hold release command signal specifying its own address, it stops the output of the hold tone from the telephone handset 20-1 in step S71, reconnects the telephone handset 20-1 to the telephone lines 16a and 16b, and resumes the call with the telephone base unit 28.

(Three-way call)
Figure 8 is a time chart showing call control of a three-way call using a telephone base unit and two telephone handsets. As in Figure 7, the two telephone repeaters 18, telephone handsets 20, and telephone handset control unit 48 that perform the three-way call are telephone repeaters 18-1, 18-2, telephone handsets 20-1, 20-2, and telephone handset control units 48-1, 48-2, respectively.

In the three-way call shown in FIG. 8, the control of steps S81 to S92 is the same as steps S51 to S62 shown in FIG. 7, so the explanation is omitted.

In the three-way call shown in FIG. 8, when a call is connected between the base station 28 and the handset 20-1, if a call command signal is sent from the telephone repeater 18-2 of the other handset 20-2 and a call to the handset 20-2 is displayed on the display 30 in step S92, a three-way call selection button is displayed on the display screen, allowing the user to select the three-way call.

Therefore, when the telephone base unit control unit 46 recognizes the selection operation of three-way calling in step S93, the process proceeds to step S94, where an incoming call command signal specifying the address of the telephone repeater 18-2 that sent the outgoing call command signal is sent to the transmission lines 12a and 12b, and the telephone handset control unit 48-2 that receives this connects the telephone handset 20-2 to the telephone lines 16a and 16b in step S95.

Then, in step S96, the telephone base unit control unit 46 sequentially transmits a three-way call command signal specifying the addresses of the telephone repeaters 18-1 and 18-2 to the transmission lines 16a and 16b. The telephone handset control units 48-1 and 48-2 that receive this transmit a predetermined message in steps S97 and S98 from the telephone handsets 20-1 and 20-2 notifying the start of a three-way call. As a result, the three-way call shown in step S99 of the telephone base unit control unit 46 and steps S100 and S101 of the telephone handset control units 48-1 and 48-2 is performed by connecting the telephone base unit 28 and the telephone handsets 20-1 and 20-2 to the telephone lines 16a and 16b.

Here, by connecting the telephone base unit 28 and multiple telephone handsets 20 to the telephone lines 16a and 16b, four-way or five-way calls can be realized. However, as the number of telephones connected to the telephone lines 16a and 16b increases, the level of the audio signals transmitted by the telephone lines 16a and 16b decreases, deteriorating the quality of the call. Therefore, three-way calls are optimal, in which three telephones, each connected to the telephone base unit 28 and two telephone handsets, are connected to the telephone lines 16a and 16b, which causes less of a decrease in audio level.

(Call control performed by connecting a maintenance telephone handset to a telephone jack)
FIG. 9 is a time chart showing call control performed when an emergency telephone handset is connected to a telephone jack.

As shown in FIG. 9, when a person carrying a maintenance telephone handset 40 inserts the plug 42 of the maintenance telephone handset 40 into the telephone jack 38 of the transmitter 36 in step S111 to contact the receiver 10, the maintenance telephone handset 40 is connected to the telephone lines 16a and 16b, causing line current to flow, and the call detection circuit unit 35 of the receiver 10 detects a drop in the line voltage in step S112 and outputs a call detection signal to the telephone base unit control unit 46.

The telephone base unit control unit 46, which has received the call detection signal from the call detection circuit unit 35, instructs the alarm unit 33 to output a ring tone from the speaker in step S113 to make a call, and then proceeds to step S114 to display a call to the maintenance telephone handset 40 on the display 30 to notify the user.

When the person in charge picks up the telephone base unit 28 installed on the receiver 10 upon receiving the ring tone in step S113, the telephone base unit control unit 46 determines in step S115 that the telephone base unit 28 is off-hook, and in step S116 instructs the connection switching unit 62 to turn on the switch circuit unit 66, thereby connecting the telephone base unit 28 to the telephone lines 16a and 16b for communication, and a communication connection is established with the maintenance telephone handset 40.

When the call is finished, the telephone base unit 28 is returned, and the telephone base unit control unit 46 determines in step S117 that the telephone base unit 28 is on-hook, and in step S118 performs a call disconnection to disconnect the telephone line 16a, 16b, thus terminating the call connection.

When the call is finished, the maintenance telephone handset 40 is removed from the telephone jack 38 in step S119 and disconnected from the telephone lines 16a and 16b, which causes the line voltage to be restored in the call detection circuit unit 35 in step S120, and the output of the notification detection signal is stopped.

[Fire alarm system with emergency telephone system and maintenance telephone system]
(Facility overview)
FIG. 10 is an explanatory diagram showing an embodiment of a fire alarm system having a call control function for emergency telephone equipment linked to an emergency broadcasting system and maintenance telephone equipment used for maintenance and inspection.

As shown in FIG. 10, transmission lines 12a and 12b for the fire alarm system, emergency telephone lines 16c and 16d for the emergency telephone system, and maintenance telephone lines 84a and 84b for the maintenance telephone system are drawn from the receiver 10 to the alert area.

A number of fire detectors 14, repeaters 15, and addressable transmitters 37, each having a transmission function and a unique address set, are connected to the transmission lines 12a and 12b. In addition, a number of telephone repeaters 18, each equipped with an emergency telephone handset 20a, are connected to the transmission lines 12a and 12b and the emergency telephone lines 16c and 16d, and the telephone repeaters 18 are each set to a unique address and have a transmission function and a call control function.

A transmitter 36 is connected to the repeater 15 of the transmission lines 12a and 12b. The transmitter 36 is provided with a transmitter button 36a, and when the transmitter button 36a is pressed to turn on in the event of a fire, a transmission signal is output to the repeater 15, and a fire notification signal is sent from the repeater 15 to the receiver 10 via the transmission lines 12a and 12b, and a fire alarm is output.

The transmitter 36 is provided with a telephone jack 38, which is connected to maintenance telephone lines 84a and 84b. When the plug 42 of the maintenance telephone handset 40a carried by the person in charge is inserted into the telephone jack 38, the maintenance telephone handset 40a is connected to the maintenance telephone lines 84a and 84b, and a call connection with the telephone base unit 28 provided in the receiver 10 is established, allowing a call to be made.

The addressable transmitter 37 is also provided with a transmitter button 37a, similar to the transmitter 36. When the transmitter button 37a is pressed to turn it on in the event of a fire, a fire notification signal is sent from the transmitter 37b via the transmission lines 12a and 12b to the receiver 10, and a fire alarm is output.

The addressable transmitter 37 is provided with a telephone jack 38, just like the transmitter 36, and the telephone jack 38 is connected to the maintenance telephone lines 84a and 84b. When the plug 42 of the maintenance telephone handset 40a carried by the person in charge is inserted into the telephone jack 38, the maintenance telephone handset 40a is connected to the maintenance telephone lines 84a and 84b, and a call connection with the telephone base unit 28 provided in the receiver 10 is established, enabling a call to be made.

The receiver 10 is provided with a telephone base unit 28 corresponding to the emergency telephone handset 20a and the maintenance telephone handset 40a.

In addition to the fire alarm system, this embodiment is also provided with an emergency broadcast system, and broadcast lines 92 are drawn from an emergency broadcast panel 90 installed in the same manager's room as the receiver 10, for example, to the security zone, for example, for each floor system, and a broadcast speaker 94 is connected to the broadcast line 92.

(Receiver functional configuration)
The receiver 10 comprises a receiving control unit 22, a transmission unit 24, an emergency telephone base unit circuit unit 26a, a maintenance telephone base unit circuit unit 26b, a telephone base unit 28, a display 30 with a touch panel, a display unit 31, an operation unit 32, an alarm unit 33 with a speaker, a notification unit 34, a call detection circuit unit 35 and a switching unit 82.

The reception control unit 22 of the receiver 10 is provided with the functions of a telephone base unit control unit 46, which are realized by the execution of a program by the CPU. The fire monitoring control unit 44 is the same as in the embodiment shown in FIG. 1, so its description is omitted.

(Telephone base unit control unit)
The telephone base unit control unit 46 performs call control for incoming calls to the emergency telephone handset 20a, call control for incoming calls to the maintenance telephone handset 40a, and call control when incoming calls to the emergency telephone handset 20a and the maintenance telephone handset 40a overlap.

The telephone repeater 18 is the same as that shown in FIG. 2, and the call detection circuit section 35 is the same as that shown in FIG. 3. The emergency telephone base unit circuit section 26a and the maintenance telephone base unit circuit section 26b are basically the same as the telephone base unit circuit section 26 in FIG. 3, but differ in that a switching section 82 is provided between the base unit telephone 28, and when an emergency call is received, the base unit telephone 28 is switched to the emergency telephone base unit circuit 26a side, and when a maintenance call is received, the base unit telephone 28 is switched to the maintenance telephone base unit circuit section 26b.

[Call Control]
The telephone base unit control unit 46 displays the operations required for call control with the telephone base unit 28 on the display 30 based on a call command signal including the caller address from the emergency telephone handset 20a via the telephone repeater 18 and the repeater 15, and/or based on a call detection signal from the call detection circuit unit 35, and performs the following call control based on screen operations, etc.

(Maintenance call received)
During regular inspections, etc., when the plug 42 of the maintenance telephone handset 40a carried by an inspection personnel is inserted into the telephone jack 38 of the transmitter 36 or addressable transmitter 37 to connect it to the maintenance telephone lines 84a, 84b, the call detection circuit unit 35 of the receiver 10 detects the line current flowing through the connection of the maintenance telephone handset 40a, and outputs a call detection signal to the telephone base unit control unit 46.

The telephone base unit control unit 46, which receives the call detection signal from the call detection circuit unit 35, displays an incoming maintenance call on the display 30, outputs a specified maintenance call incoming tone (maintenance call ring tone) from the speaker of the alarm unit 33, and switches the telephone base unit 28 to the maintenance telephone base unit circuit unit 26b by the switching unit 82.

When a disaster prevention manager or the like on the receiver 10 side who has received such an incoming maintenance call picks up the telephone base unit 28, the telephone base unit 28 detects that the telephone base unit 28 is off-hook and is connected to the maintenance telephone handset 40a that made the call via the maintenance telephone base unit circuit section 26b and the maintenance telephone lines 84a, 84b, allowing the necessary call to be made.

(Emergency call)
If a monitor or the like discovers a fire during patrol, when he picks up the emergency telephone handset 20a installed nearby, the hook switch is turned on and a call command signal including the caller's address is transmitted to the receiver 10 via the telephone repeater 18 and the repeater 15. The telephone base unit control unit 46 of the receiver 10 which receives the call command signal from the emergency telephone handset 20a displays an incoming emergency call on the display 30 together with the caller's location based on the caller's address, outputs a predetermined emergency call incoming tone (emergency call tone) from the speaker of the alarm unit 33, and switches the telephone base unit 28 to the emergency telephone base unit circuit unit 26a by the switching unit 82.

When a disaster prevention manager or the like on the receiver 10 side who has received such an emergency call picks up the telephone base unit 28, the telephone base unit 28 detects that the telephone base unit 28 is off-hook and connects to the handset 20a that made the call via the emergency telephone lines 16c, 16d, allowing the necessary call to be made.

When the telephone base unit control unit 46 of the receiver 10 receives a call command signal by picking up the emergency telephone handset 20a via the telephone repeater 18 and the repeater 15, it instructs the notification unit 34 to output a fire notification signal including the area where the fire has occurred based on the caller address to the emergency broadcast panel 90 within a predetermined time, for example within 10 seconds.

The emergency broadcast panel 90, which receives the fire transmission signal from the receiver 10, designates the floor where the fire broke out and the floor directly above it as the fire outbreak area as its broadcasting zone and broadcasts the fire. For example, this fire broadcast may say, "There's a fire. There's a fire. A fire has broken out in the XX area. Please remain calm and evacuate." In addition, when a specified time has passed since the start of the emergency broadcast, the emergency broadcast panel 90 broadcasts the emergency broadcast to the entire building simultaneously in all broadcasting zones.

(Duplicate emergency calls)
In addition, when calls from multiple emergency telephone handsets 20a overlap, the telephone base unit control unit 46 of the receiver 10 displays the multiple call sources on the display 30, and controls to connect to the emergency telephone handset 20a of the call source selected by screen operation. At this time, the telephone base unit control unit 46 controls to output a hold tone from the emergency telephone handsets that were not selected.

(Duplicate calls from emergency and maintenance calls)
In addition, when the emergency and maintenance telephone handsets 20a and 40a receive the same call, the base telephone control unit 46 of the receiver 10 displays the emergency and maintenance calls on the display 30 and performs control to connect the call to the emergency or maintenance telephone handset 20a or 40a selected by screen operation. At this time, the base telephone control unit 46 performs control to output a hold tone from the telephone handset that was not selected. Priorities may be set in advance for the emergency and maintenance calls, and the caller with the highest priority may be selected for call connection.

(Alternative display of emergency and maintenance telephones)
Also, an incoming call to the emergency telephone handset 20a may be displayed on the display 30, and an incoming call to the maintenance telephone handset 40a may be displayed by a maintenance telephone light disposed in the panel. Since the emergency telephone handset 20a transmits an emergency call signal including a unique caller address, it is preferable to indicate the caller on the display 30 since the installation location of the emergency telephone handset 20a can be recognized.

(Communication of connection location information when connecting a maintenance telephone handset)
When the maintenance telephone handset 40a is connected to the transmitter 36 or the addressable transmitter 37, the transmitter 36 or the addressable transmitter 37 detects the connection of the plug and transmits address information on the transmission circuit to the receiver 10, and the receiver 10 may display information specifying the transmitter 36 or the addressable transmitter 37 to which the maintenance telephone handset 40a is connected from the information. By making it possible to display whether the call originated from the emergency telephone handset 20a or the maintenance telephone handset 40a, it becomes possible to help determine which call to prioritize.

[Modifications of the present invention]
(Telephone Jack)
The above embodiment shows an example in which a telephone jack is provided on the transmitter, but a telephone jack may be provided on an appropriate terminal device as necessary. Furthermore, the maintenance telephone equipment is not limited to a portable type, and may be a maintenance telephone handset that is fixedly installed in the security zone and used by being inserted into a telephone jack.

The telephone jack may also be provided on the receiver 10. For example, the positive and negative sides of the telephone jack are connected via capacitors between the telephone lines 16a and 16b drawn out from the call detection circuit unit 35 shown in FIG. 3 to the terminal side. In this case, a call connection can be established between the maintenance telephone handsets by plugging them into the receiver's telephone jack and the transmitter's telephone jack.

(Maintenance handset priority and handset hold tone)
In the above embodiment, when the telephone base unit control unit 46 detects a connection of the maintenance telephone handset 40 to the telephone jack 38 during a call connection between the telephone base unit 28 and any of the emergency telephone handsets 20, it notifies of a call to the maintenance telephone handset 40a, switches the call connection to the maintenance telephone handset 40, and sends a hold command signal specifying the address of the telephone relay unit 18 of the emergency telephone handset 20 that is in use, thereby disconnecting the emergency telephone handset 20 from the telephone lines 16a, 16b and outputting a specified hold sound.

As a result, when the maintenance telephone handset 40 is connected to the telephone jack 38 during a call between the telephone base unit 28 and the emergency telephone handset 20, the previous call connection between the telephone base unit 28 and the emergency telephone handset 20 is put on hold and the call with the maintenance telephone handset 40 can be made with priority.

In addition, when the call between the telephone base unit 28 and the maintenance telephone handset 40 ends, the telephone base unit control unit 46 may send a hold release command signal specifying the address of the telephone relay unit 18 of the emergency telephone handset 20 on hold, to connect the emergency telephone handset 20 to the telephone lines 16a and 16b, thereby restoring the call between the telephone base unit 28 and the emergency telephone handset 20.

(Call between telephone handsets)
The above embodiment takes as an example call control between the receiver's telephone base unit and a telephone handset installed in a security area, but is not limited to this. By providing an operation display unit that inputs a telephone number into the telephone repeater to make a call, it is possible to enable calls to be made between telephone handsets by calling one telephone handset specifying another telephone handset.

(Hands-free calling function)
The above embodiment takes as an example a call between a telephone base unit and a telephone handset, but is not limited to this. In addition to each of the telephone base unit of the receiver and the telephone handset of the telephone repeater, a microphone and speaker may be installed on a panel surface near the telephone, and a hands-free calling function may be provided that allows the telephone to be switched to a microphone and speaker by operating a specified switch, allowing a call to be made without using the telephone.

(P-type receiver)
The above embodiment takes as an example a fire alarm system in which an R-type fire detector is connected via a transmission line from an R-type receiver, but similar communication control can also be achieved in a fire alarm system in which an addressable fire detector with a transmission function and an address is set on the detector line drawn from a P-type receiver, by sending and receiving various command signals using the detector line.

(others)
Furthermore, the present invention includes appropriate modifications that do not impair the objects and advantages of the present invention, and is not limited to the numerical values shown in the above embodiment.

10: Receiver 12a, 12b: Transmission line 14: Fire detector 15: Repeater 16a, 16b: Telephone line 16c, 16d: Emergency telephone line 18: Telephone repeater 20: Telephone handset 20a: Emergency telephone handset 22: Reception control section 24, 50: Transmission section 26: Telephone base unit circuit section 26a: Emergency telephone base unit circuit section 26b: Maintenance telephone base unit circuit section 28: Telephone base unit 30: Display 35: Speech detection circuit section 36: Transmitter 37: Addressable transmitter 38: Telephone Jack 40: Maintenance telephone handset 40a: Maintenance telephone handset 44: Fire monitoring control unit 46: Telephone base unit control unit 45, 72: Handset 47, 74: Transmitter 48: Telephone handset control unit 52, 62: Connection switching unit 54, 64: Control sound generating unit 56, 66: Switch circuit unit 58, 68: Transformer 60, 70: Hook switch 61, 94: Speaker 76, 78, 80: Resistor 82: Switching unit 84a, 84b: Maintenance telephone line 90: Emergency broadcast panel 92: Broadcast line

Claims (3)

A fire alarm system comprising a terminal device including a telephone repeater connected to a transmission line extending from a receiver to a security zone, and the telephone repeater connected to a telephone line also extending from the receiver to the security zone and connected to a telephone jack,
The receiver includes:
A call connection is possible between a first telephone handset connected to the telephone line via the telephone repeater and a second telephone handset connected to the telephone line via the telephone jack,
A call connection with the first handset is controlled by transmitting and receiving a predetermined call control signal via the transmission line between the first handset and the telephone repeater to which the first handset is connected ;
A call connection with the second handset is controlled based on a connection state of the second handset to the telephone jack;
A fire alarm system characterized in that when connection of the second telephone handset to the telephone jack is detected during a call connection with the first telephone handset, the system switches to a call connection with the second telephone handset.
The fire alarm system according to claim 1,
This fire alarm system is characterized in that when the receiver detects connection of the second telephone handset to the telephone jack while a call is connected to the first telephone handset and switches to a call connection with the second telephone handset, it sends a hold command signal via the transmission line to a telephone repeater connected to the first telephone handset that was previously connected, causing a hold sound to be output from the first telephone handset that was previously connected.
A transmission line extending from the receiver to the security zone and connected to terminal equipment including a telephone repeater;
a first telephone line extending from the receiver to the security zone and connected to the telephone repeater;
a second telephone line extending from said receiver into said security zone and connected to a telephone jack;
A fire alarm system provided with :
The receiver includes:
storing address information capable of identifying the telephone repeater;
A call connection is possible between a first telephone handset connected to the first telephone line via the telephone repeater and a second telephone handset connected to the second telephone line via the telephone jack,
A call connection with the first handset is controlled by transmitting and receiving a predetermined call control signal via the transmission line between the first handset and the telephone repeater to which the first handset is connected ;
A call connection with the second handset is controlled based on a connection state of the second handset to the telephone jack ;
When an incoming call is received from the first handset, a display is performed to indicate that an incoming call has been received so that the first handset that is the source of the incoming call can be identified based on the address information of the telephone repeater to which the first handset is connected;
A fire alarm system characterized in that, when an incoming call is received from said second telephone handset, a display is given to indicate that an incoming call has been received from said second telephone handset .

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