Non-addressing extension set control circuit of fire-fighting telephone and non-addressing extension set

Abstract

The utility model relates to a non-addressing extension set control circuit of a fire-fighting telephone and a non-addressing extension set, which are characterized in that a telephone receiver disconnection detection circuit is arranged in the circuit, so that after a telephone receiver is disconnected, a constant current different from an off-hook state is generated, and the current can be detected by an addressing jack, so that a host can be timely informed to report a fault, and the safety of the fire-fighting telephone is improved. And timely maintenance is facilitated. When the receiver line is not connected to the non-addressing jack base, the receiver line can be detected by the receiver line-dropping detection circuit, a current path is generated, a filtering capacitor is arranged in the receiver line-dropping detection circuit, so that the voltage of a triode is stable enough, misoperation is avoided, meanwhile, a current limiting circuit is arranged, so that the current is more stable after the receiver line drops, and the service life of the receiver line is prolonged. The current after the earphone is disconnected and falls off can be distinguished from the off-hook state current more easily, and the detection is more accurate. And a protection circuit is cooperatively arranged to protect the whole circuit, so that the safety of the control circuit is improved.

Description

Technical Field

[0001] This utility model relates to the field of non-addressable extension control circuits and non-addressable extensions, and particularly to a non-addressable extension control circuit and a non-addressable extension for a fire telephone. Background Technology

[0002] Fire protection products refer to products specifically designed for fire prevention, firefighting and rescue, fire protection, refuge, and escape. Fire telephone systems play a crucial role in fire control; therefore, the long-term stable and reliable operation of a fire telephone system depends on several factors. These include the one-to-one connection between the fire telephone main unit and extension units via software control, the effective and stable transmission of bus control signals and voice signals, cost savings during installation, simplified installation and commissioning procedures, and reduced maintenance costs. When a fire alarm occurs, it provides convenient and rapid communication, making it an indispensable communication device in fire control and alarm systems. Fire telephone extension units are a vital component of automatic fire alarm telephone systems.

[0003] Currently, most fire telephone extensions are non-addressable extensions connected to jacks (i.e., extensions without addresses). If the handset wire comes loose, it cannot be detected during standby mode. The handset detachment is only discovered when the phone is needed, preventing the main unit from being notified of the fault in a timely manner. This is because non-addressable extensions lack an MCU (Microcontroller Unit), making it impossible to detect a dropped handset. Furthermore, non-addressable extensions are not directly connected to the main bus but rather to a branch line connected to an addressable jack, thus preventing direct communication with the main unit and inability to directly inform it. Utility Model Content

[0004] The technical problem this invention aims to solve is that when the handset wire of an existing non-addressable extension phone becomes detached, it cannot be detected in standby mode; the detachment is only discovered when the phone is needed, preventing the main unit from being promptly notified of the fault. To address these shortcomings of the prior art, this invention provides a control circuit for a non-addressable extension phone for a fire telephone and a fire telephone itself.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:

[0006] A non-addressable extension control circuit for a fire telephone is constructed, including a branch connected to an addressable jack, a call circuit connected to the branch, and a handset connected to the call circuit. The control circuit also includes a handset disconnection detection circuit connected to the branch and the handset.

[0007] A branch circuit is used to connect to an addressing socket to provide electrical signals to the control circuit.

[0008] The call circuit is connected to the branch circuit and allows voice transmission after the handset is picked up, and generates the first current after the handset is picked up;

[0009] The earpiece is connected to the communication circuit and converts voice signals into electrical signals or vice versa.

[0010] The earpiece disconnection detection circuit is connected to the earpiece and the branch circuit. The earpiece disconnection detection circuit generates a second current after the earpiece disconnects, and the second current is less than the first current.

[0011] Preferably, the earpiece disconnection detection circuit is also connected to a current limiting circuit. When the earpiece disconnection detection circuit detects that the actual current is greater than the second current, the current limiting circuit stabilizes the actual current to the second current.

[0012] Preferably, the earpiece disconnection detection circuit includes a 57th resistor connected to the earpiece, a 4th transistor and a 30th resistor connected to the 57th resistor, a 14th resistor connected to the 30th resistor, a 5th transistor connected to the 4th transistor and the 14th resistor, and a branch connecting the 5th transistor and the 14th resistor.

[0013] Preferably, the earpiece disconnection detection circuit further includes a 32nd capacitor connected to the 57th resistor and the 4th transistor, and a 25th capacitor connected to the 14th resistor and the 30th resistor.

[0014] Preferably, the current limiting circuit includes a sixth transistor and a fifty-sixth resistor connected to the earpiece disconnection detection circuit. When the actual current is greater than the second current, the sixth transistor is turned on and pulls down the base voltage of the fourth transistor to turn it off.

[0015] Preferably, the current limiting circuit further includes a thirty-eighth capacitor connected to the fifty-sixth resistor.

[0016] Preferably, the control circuit further includes a surge and electrostatic protection circuit connected to the branch, and a polarity protection circuit connected to the surge and electrostatic protection circuit. The call circuit and the handset drop detection circuit are both connected to the polarity protection circuit.

[0017] Preferably, the surge and electrostatic discharge protection circuit includes a bidirectional breakdown diode connected to the branch, the polarity protection circuit includes a bridge rectifier diode connected to the bidirectional breakdown diode, and the handset disconnection detection circuit and the call circuit are connected to the bridge rectifier diode.

[0018] Preferably, the handset includes a microphone and a receiver, the microphone and receiver are connected to a communication circuit, and the receiver is connected to a handset drop detection circuit.

[0019] A non-addressable extension for a fire telephone is constructed. The non-addressable extension uses the control circuit of a non-addressable extension for a fire telephone as described above to detect handset disconnection.

[0020] The beneficial effects of this invention are as follows: By incorporating a handset disconnection detection circuit into the circuit, a constant current distinct from the off-hook state is generated when the handset is disconnected. This current can be detected by the addressable jack, allowing the host to promptly report a fault for timely repair. The handset disconnection detection circuit can detect when the handset cable is not connected to the non-addressable jack base, creating a current path. The circuit includes a filter capacitor to ensure sufficient voltage stability of the transistor, preventing malfunctions. A current-limiting circuit further stabilizes the current after the handset disconnects, making it easier to distinguish the disconnected current from the off-hook current, resulting in more accurate detection. Furthermore, a protection circuit is incorporated to protect the entire circuit, improving the safety of the control circuit. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the utility model will be further described below in conjunction with the accompanying drawings and embodiments. The drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a simplified schematic diagram of a fire telephone system according to a preferred embodiment of the present invention;

[0023] Figure 2 This is a simplified schematic diagram of a non-addressable extension system according to a preferred embodiment of the present invention;

[0024] Figure 3 This is a schematic block diagram of the non-addressable extension control circuit of a preferred embodiment of the present invention.

[0025] Figure 4 The following is a detailed circuit diagram of the non-addressable extension control circuit of a preferred embodiment of this utility model. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, a clear and complete description will be provided below in conjunction with the technical solutions in the embodiments of this utility model. Obviously, the described embodiments are some, but not all, embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0027] A preferred embodiment of this utility model provides a non-addressable extension control circuit for a fire telephone; such as... Figure 1As shown, a fire telephone typically includes a fire telephone main unit and non-addressable extensions. The main unit's bus is connected to an addressable jack at one end, and the other end of the addressable jack is connected to a non-addressable extension. The non-addressable extension includes a base, on which a non-addressable extension control circuit is installed. The non-addressable extension is connected to a handset, which includes a microphone and a receiver. Both the microphone and the receiver are connected to the non-addressable extension control circuit.

[0028] Specifically, such as Figures 2-3 As shown, the non-addressable extension control circuit includes a branch 10 connected to the right side of the addressable jack, and a surge and electrostatic protection circuit 20 connected to the branch. The surge and electrostatic protection circuit 20 is connected to a polarity protection circuit 30, which is connected to a call circuit 50 and a current limiting circuit 40. The call circuit is connected to a microphone 70 and a receiver 80. The current limiting circuit 40 is connected to a handset disconnection detection circuit 60, which is connected to the receiver 80. When the handset wire of the non-addressable telephone extension becomes disconnected, the handset disconnection detection circuit detects and generates a constant current. This constant current is different from other operating currents such as off-hook, allowing the addressable jack to detect it and notify the host to report a fault. The fault is then communicated to the host via the bus.

[0029] Furthermore, such as Figure 4 As shown, the surge and electrostatic protection circuit 20 includes an interface Z1 connected to the right side of the addressing socket via a branch line. The Z1 interface of the non-addressing extension is connected to the input electrical signal of the non-addressing extension control circuit. The Z1 interface is connected to a first bidirectional breakdown diode D1, which suppresses instantaneous high voltage or current and prevents electrostatic discharge damage. The polarity protection circuit 30 includes a bridge rectifier diode U6 connected to the Z1 interface. Due to the setting of the bridge rectifier diode U6, the two wires of the Z1 interface can be connected arbitrarily and can work without considering the positive and negative polarities, making wiring more convenient.

[0030] Furthermore, such as Figure 4As shown, the handset disconnection detection circuit 50 includes a fourteenth resistor R14 connected to the other end of the bridge rectifier diode U6. The other end of the fourteenth resistor R14 is grounded through the twenty-fifth capacitor C25. The other end of the fourteenth resistor R14 is also connected to a thirtieth resistor R30. The other end of the thirtieth resistor R30 is connected to the base of the fourth transistor Q4. The other end of the fourteenth resistor R14 is connected to the collector of the fourth transistor Q4. The emitter of the fourth transistor Q4 is connected to the base of the fifth transistor Q5. The collector of the fifth transistor Q5 is connected to the bridge rectifier diode U6. The other end of the thirtieth resistor R30 is also grounded through the thirty-second capacitor C32, and connected to the receiver through the fifty-seventh resistor R57. The current limiting circuit 40 includes a fifty-sixth resistor R56 connected to the emitter of the fifth transistor Q5, with the other end of R56 grounded; and a thirty-eighth capacitor C38 connected to the emitter of the fifth transistor Q5 and grounded, with the other end of C38 grounded; a sixth transistor Q6 connected to the emitter of the fifth transistor Q5; the emitter of the fifth transistor Q5 connected to the base of the sixth transistor Q6; the emitter of the sixth transistor Q6 grounded; and the collector of the sixth transistor Q6 connected to the base of the fourth transistor Q4. The communication circuit 50 is connected to the bridge rectifier diode U6 via switch S1. The communication circuit uses a seventh chip U7, model TEA1062ANG-S16-R, which, along with surrounding resistors and capacitors, forms the communication circuit. The seventh chip U7 is connected to the microphone and receiver.

[0031] When using, such as Figure 4As shown, connecting branch 10 to the addressing jack powers the control circuit. In standby mode, switch S1 is open; when the handset is picked up, switch S1 is closed, and the call circuit operates, enabling voice calls. The microphone picks up sound, converting the spoken voice signal into an electrical signal. This signal is then transmitted through the non-addressing extension control circuit, the branch addressing module, and the bus to the main unit. The receiver converts the electrical signal back into a voice signal and plays it back. When the handset cable is not connected to the non-addressing extension jack base, the handset disconnection detection circuit detects the disconnection and creates a current path. Resistor R57 is connected to the receiver's positive terminal on the handset cable. Under normal conditions, since the receiver's DC resistance is 150 ohms, after voltage division, the base voltage of transistor Q4 is approximately 0V. At this time, transistors Q4 and Q5 are cut off, and no current flows through resistor R57. When the handset cord detaches, resistor R57 (57) will be floating. At this time, the base voltage of transistor Q4 will rise to a level that turns on both transistors Q4 and Q5. Current will then flow through resistor R56 (56), indicating that the handset cord has detached. Simultaneously, capacitor C32 (32) filters out interference, ensuring a sufficiently stable base voltage for transistor Q4 and preventing malfunctions. Furthermore, when the handset cord detaches on a non-addressed extension, the current generated by the conduction of transistors Q4 and Q5 is limited to 1.3mA by the current-limiting circuit. This current value differs from the normal handset off-hook current, which is generally greater than 4mA. Simultaneously, when transistor Q5 is turned on, current flows through capacitor C38. If the current exceeds 1.3mA, transistor Q6 will turn on. Then, transistor Q6 will pull down the base voltage of transistor Q4, causing Q4 to turn off, ultimately stabilizing the current at 1.3mA. Capacitor C38 also further stabilizes the current. Since the addressing jack is connected to the non-addressing extension and can distinguish between 1.3mA and 4mA currents, when a 1.3mA current is detected, a feedback code will be sent to the host, notifying the host of a fault where the handset cable of the non-addressing extension has become disconnected.

[0032] A preferred embodiment of this utility model provides a non-addressable extension of a fire telephone. The non-addressable extension contains a non-addressable extension control circuit as described above. This control circuit detects dropped handsets and promptly feeds back the abnormal detection results to the main unit. The specific control circuit content is the same as described above and will not be repeated here.

[0033] It should be understood that this utility model has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of this utility model. Furthermore, under the teachings of this utility model, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of this utility model.

Claims

1. A non-addressable extension control circuit for a fire telephone, comprising a branch line connected to an addressable jack, a communication circuit connected to the branch line, and a handset connected to the communication circuit, characterized in that: The control circuit also includes an earpiece disconnection detection circuit connected to the branch circuit and the earpiece; A branch circuit is used to connect to an addressing socket to provide electrical signals to the control circuit. The call circuit is connected to the branch circuit and allows voice transmission after the handset is picked up, and generates the first current after the handset is picked up; The earpiece is connected to the communication circuit and converts voice signals into electrical signals or vice versa. The earpiece disconnection detection circuit is connected to the earpiece and the branch circuit. The earpiece disconnection detection circuit generates a second current after the earpiece disconnects, and the second current is less than the first current.

2. The control circuit according to claim 1, characterized in that: The earpiece disconnection detection circuit is also connected to a current limiting circuit. When the earpiece disconnection occurs, if the earpiece disconnection detection circuit detects that the actual current is greater than the second current, the current limiting circuit will stabilize the actual current to the second current.

3. The control circuit according to claim 1, characterized in that: The earpiece disconnection detection circuit includes a 57th resistor connected to the earpiece, a 4th transistor and a 30th resistor connected to the 57th resistor, a 14th resistor connected to the 30th resistor, a 5th transistor connected to the 4th transistor and the 14th resistor, and a branch connecting the 5th transistor and the 14th resistor.

4. The control circuit according to claim 3, characterized in that: The earpiece disconnection detection circuit also includes a 32nd capacitor connected to the 57th resistor and the 4th transistor, and a 25th capacitor connected to the 14th resistor and the 30th resistor.

5. The control circuit according to claim 2, characterized in that: The current limiting circuit includes a sixth transistor and a fifty-sixth resistor connected to the earpiece disconnection detection circuit. When the actual current is greater than the second current, the sixth transistor turns on and pulls down the base voltage of the fourth transistor, causing the fourth transistor to turn off.

6. The control circuit according to claim 5, characterized in that: The current limiting circuit also includes a 38th capacitor connected to the 56th resistor.

7. The control circuit according to any one of claims 1-6, characterized in that: The control circuit also includes a surge and electrostatic protection circuit connected to the branch, and a polarity protection circuit connected to the surge and electrostatic protection circuit. The call circuit and the handset drop detection circuit are both connected to the polarity protection circuit.

8. The control circuit according to claim 7, characterized in that: The surge and electrostatic discharge protection circuit includes a bidirectional breakdown diode connected to the branch circuit, the polarity protection circuit includes a bridge rectifier diode connected to the bidirectional breakdown diode, and the handset disconnection detection circuit and the call circuit are connected to the bridge rectifier diode.

9. The control circuit according to claim 1, characterized in that: The handset includes a microphone and a receiver, which are connected to a communication circuit, and the receiver is connected to a handset drop detection circuit.

10. A non-addressable extension for a fire telephone, characterized in that: The non-addressable extension uses the non-addressable extension control circuit of a fire telephone as described in any one of claims 1-9 to detect handset disconnection.

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