Controllable audio switching circuit and device

Abstract

The utility model provides a controllable audio switching circuit, which relates to the technical field of financial equipment and comprises an explosion-proof microphone, a first relay, a second relay, a main control unit, a switching terminal and a machine sound box connected with the switching terminal, one end of the explosion-proof microphone is connected with one end of the switching terminal through the first relay, the other end of the switching terminal is connected with the other end of the explosion-proof microphone, and the second relay is connected with the switching terminal in parallel; the main control unit is electrically connected with the first relay and the second relay so as to control the first relay and the second relay to be connected or disconnected. According to the utility model, the problem that the explosion-proof microphone and the machine sound equipment cannot be independently controlled in the prior art is solved.

Description

Technical Field

[0001] This utility model relates to the technical field of financial equipment, and in particular to a controllable audio switching circuit and device. Background Technology

[0002] Reference to the working process of existing audio switcher devices Figure 1 As shown, the explosion-proof microphone and the equipment speaker can be automatically switched via a switching terminal. When the explosion-proof microphone is on, the switching terminal is in a conductive state, and the equipment speaker emits sound. When the customer picks up the explosion-proof microphone, the switching terminal is disconnected, and the explosion-proof microphone emits sound.

[0003] However, this structure cannot achieve individual control of the explosion-proof microphone and the equipment's audio, resulting in its narrow applicability and inconvenience in use. Utility Model Content

[0004] In view of the shortcomings of the existing technology, the present invention provides a controllable audio switching circuit and device, which solves the problem that the existing technology cannot achieve individual control of explosion-proof microphones and machine speakers, resulting in narrow applicability and inconvenience in use.

[0005] At least one embodiment of this utility model provides a controllable audio switching circuit, including: an explosion-proof microphone, a first relay, a second relay, a main control unit, a switching terminal, and a machine speaker connected to the switching terminal, wherein...

[0006] One end of the explosion-proof microphone is connected to one end of the switching terminal via the first relay, and the other end of the switching terminal is connected to the other end of the explosion-proof microphone. The second relay is connected in parallel with the switching terminal.

[0007] The main control unit is electrically connected to the first relay and the second relay respectively, so as to control the first relay and the second relay to engage or disengage.

[0008] The technical solution disclosed in this utility model has at least the following beneficial effects:

[0009] With the above settings, when switching to microphone mode is required, the main control unit controls the first and second relays to disconnect, thus disconnecting the switching terminal's control over the explosion-proof microphone, allowing the explosion-proof microphone to input normally. When switching to equipment audio mode is required, the main control unit controls the first relay to disconnect and the second relay to engage, short-circuiting the explosion-proof microphone and preventing input, allowing the equipment audio to output normally. When switching to automatic switching mode is required, the main control unit controls the first relay to engage and the second relay to disconnect. At this time, the communication connection of the circuit module has been restored to the existing circuit design to perform automatic switching mode normally. In this mode, when the user picks up the explosion-proof microphone, the switching terminal control enables normal input from the explosion-proof microphone; when the user hangs up the explosion-proof microphone, the switching terminal control enables normal output from the equipment audio.

[0010] With the above settings, this utility model retains the automatic switching mode of the original audio switching circuit, and also realizes the independent controllability of the explosion-proof microphone and the machine's sound system, which improves the applicability of the circuit and makes it more convenient to use.

[0011] In one embodiment of the controllable audio switching circuit provided by this utility model, the main control unit is configured as follows:

[0012] Upon receiving a first preset signal, the first relay is controlled to engage, and the second relay is controlled to disengage.

[0013] Upon receiving a second preset signal, the first relay is controlled to disconnect, and the second relay is controlled to disconnect.

[0014] Upon receiving a third preset signal, the first relay is controlled to engage, and the second relay is controlled to engage.

[0015] In one embodiment of the controllable audio switching circuit provided by this utility model, the circuit further includes a status monitoring unit;

[0016] One end of the status monitoring unit is connected to the explosion-proof microphone or the switching terminal, and the other end of the status monitoring unit is connected to the main control unit to transmit the connection status between the explosion-proof microphone and the switching terminal to the main control unit.

[0017] The technical solution disclosed in this utility model has at least the following beneficial effects:

[0018] The aforementioned status monitoring circuit also enables the query of the explosion-proof microphone's status. When entering automatic switching mode, the explosion-proof microphone can be suspended or picked up based on the connection status between the microphone and the switching terminal to determine whether it is in a suspended or picked-up state, and this status is fed back to the main control unit, thereby realizing the monitoring of the explosion-proof microphone's status.

[0019] In one embodiment of the controllable audio switching circuit provided by this utility model, the status monitoring unit includes an optical coupler, wherein,

[0020] The anode of the optical coupler is connected to the power supply voltage, the cathode of the optical coupler is connected to the explosion-proof microphone or switching terminal, the transmitter of the optical coupler is grounded, and the transmitter of the optical coupler is connected to the power supply voltage and the main control unit respectively.

[0021] The technical solution disclosed in this utility model has at least the following beneficial effects:

[0022] By using an optocoupler, the signal between the explosion-proof microphone and the switching terminal is isolated from the signal between the main control unit, thus protecting the main control unit.

[0023] In one embodiment of the controllable audio switching circuit provided by this utility model, the circuit further includes a resistor R2 and a switching transistor Q1, wherein,

[0024] The main control unit is connected to the control terminal of the switching transistor Q1 through the resistor R2, and the power supply voltage is grounded sequentially through the other two ends of the switching transistor Q1 and the coil of the first relay.

[0025] The technical solution disclosed in this utility model has at least the following beneficial effects:

[0026] By using the switching transistor Q1, when it receives a low-level signal or a high-level signal from the main control unit at its control terminal, its other two terminals can be turned on or off, so as to control the energization of the coil of the first relay and make the first relay energized or de-energized.

[0027] In a controllable audio switching circuit provided in one embodiment of this utility model, the switching transistor Q1 is a PNP transistor Q1, the main control unit is connected to the base of the PNP transistor Q1 through the resistor R2, and the power supply voltage is grounded through the emitter, collector and coil of the PNP transistor Q1 in sequence.

[0028] The main control unit is configured to set the base of the PNP transistor Q1 to a low level when it receives a first preset signal or a third preset signal; and to set the base of the PNP transistor Q1 to a high level when it receives a second preset signal.

[0029] In one embodiment of the present invention, a controllable audio switching circuit is provided, which further includes a freewheeling diode D1, wherein the freewheeling diode D1 is connected in parallel with the coil of the first relay.

[0030] The technical solution disclosed in this utility model has at least the following beneficial effects:

[0031] By setting the freewheeling diode D1, the coil of the first relay can be discharged when it changes from being energized to being de-energized.

[0032] In one embodiment of the present invention, a controllable audio switching circuit is provided, which further includes a light-emitting diode LED1 and a resistor R3. The anode of the light-emitting diode LED1 is connected to the collector of the PNP transistor Q1 through the resistor R3, and the cathode of the light-emitting diode LED1 is grounded.

[0033] The technical solution disclosed in this utility model has at least the following beneficial effects:

[0034] The coil status of the first relay can be monitored by setting LED1.

[0035] In one embodiment of the controllable audio switching circuit provided by this utility model, the circuit further includes a resistor R5, a PNP transistor Q2, and a freewheeling diode D2, wherein,

[0036] The main control unit is connected to the base of the PNP transistor Q2 through the resistor R5, and the power supply voltage is grounded in sequence through the emitter, collector and coil of the PNP transistor Q2 and the second relay.

[0037] The main control unit is configured to set the base of the PNP transistor Q2 to a low level when it receives a third preset signal; and to set the base of the PNP transistor Q2 to a high level when it receives a first preset signal or a second preset signal.

[0038] The freewheeling diode D2 is connected in parallel with the coil of the second relay.

[0039] In one embodiment of the present invention, a controllable audio switching circuit is provided, which further includes a light-emitting diode (LED2) and a resistor R6. The anode of the LED2 is connected to the collector of the PNP transistor Q2 through the resistor R6, and the cathode of the LED2 is grounded.

[0040] This utility model also provides an audio switcher device for financial self-service machines, including a controllable audio switching circuit as described above. Attached Figure Description

[0041] Figure 1 This is a schematic diagram showing the connection relationships of the explosion-proof microphone, switching terminals, and equipment audio in an existing audio switching device.

[0042] Figure 2 This is a schematic block diagram of the circuit structure of this utility model;

[0043] Figure 3 This is a schematic block diagram of the circuit structure of another embodiment of the present invention;

[0044] Figure 4 This is a flowchart illustrating the workflow of this utility model.

[0045] Figure 5 A schematic diagram of the minimum system control circuit for the main control unit;

[0046] Figure 6 A schematic diagram of the serial communication circuit of the main control unit;

[0047] Figure 7 A schematic diagram of the first and second relays and their related circuit structures;

[0048] Figure 8 This is the circuit for the condition monitoring unit. Detailed Implementation

[0049] The principles and features of this utility model are described below with reference to the accompanying drawings. The examples given are only for explaining this utility model and are not intended to limit the scope of this utility model.

[0050] This utility model provides a controllable audio switching circuit, please refer to [link / reference here]. Figure 2 As shown, it includes: an explosion-proof microphone, a first relay, a second relay, a main control unit, a switching terminal, and a machine audio device connected to the switching terminal, wherein...

[0051] One end of the explosion-proof microphone is connected to one end of the switching terminal via the first relay, and the other end of the switching terminal is connected to the other end of the explosion-proof microphone. The second relay is connected in parallel with the switching terminal.

[0052] The main control unit is electrically connected to the first relay and the second relay respectively, so as to control the first relay and the second relay to engage or disengage.

[0053] The main control unit is configured as follows:

[0054] Upon receiving a first preset signal, the first relay is controlled to engage, and the second relay is controlled to disengage.

[0055] Upon receiving a second preset signal, the first relay is controlled to disconnect, and the second relay is controlled to disconnect.

[0056] Upon receiving a third preset signal, the first relay is controlled to engage, and the second relay is controlled to engage.

[0057] With the above settings, when switching to microphone mode is required, the main control unit receives a second preset signal, the first relay disconnects and the second relay disconnects, thus disconnecting the switching terminal's control over the explosion-proof microphone, allowing the explosion-proof microphone to input normally. When switching to device audio mode is required, the main control unit receives a third preset signal, the first relay disconnects and the second relay engages, short-circuiting the explosion-proof microphone and preventing input, allowing the device audio to output normally. When switching to automatic switching mode is required, the main control unit receives a first preset signal, the first relay engages and the second relay disconnects. At this time, the communication connection of the circuit module is restored to the existing circuit design to perform automatic switching normally. In this mode, when the user picks up the explosion-proof microphone, the switching terminal controls the normal input of the explosion-proof microphone; when the user hangs up the explosion-proof phone, the switching terminal controls the normal output of the device audio.

[0058] This invention retains the automatic switching mode of the original audio switching circuit, and also realizes the separate controllability of the explosion-proof microphone and the machine's audio equipment, which improves the applicability of the circuit and makes it more convenient to use.

[0059] In another embodiment, please refer to [reference here]. Figure 3 As shown, this circuit also includes a status monitoring unit;

[0060] One end of the status monitoring unit is connected to the explosion-proof microphone or the switching terminal, and the other end of the status monitoring unit is connected to the main control unit to transmit the connection status between the explosion-proof microphone and the switching terminal to the main control unit.

[0061] The aforementioned status monitoring circuit also enables the query of the explosion-proof microphone's status. When entering automatic switching mode, the explosion-proof microphone can be suspended or picked up based on the connection status between the microphone and the switching terminal to determine whether it is in a suspended or picked-up state, and this status is fed back to the main control unit, thereby realizing the monitoring of the explosion-proof microphone's status.

[0062] In the above embodiments, the main control unit includes a minimum control circuit system and a serial communication circuit, wherein, reference is made herein. Figure 5As shown, the minimum control circuit system includes chip U2, capacitor C7, and resistor R4. The specific model of chip U2 is STC12C5608AD_LQFP32. The power supply voltage is grounded through capacitor C7 and resistor R4 in sequence. Capacitor C7 and resistor R4 are connected to the RST port of chip U2. The clock signal terminals XTAL1 and XTAL2 of chip U2 are connected to a clock signal circuit. The SG2 control signal issued by chip U2 is electrically connected to the first relay through its P0.2 port, and the SG3 control signal issued by chip U2 is electrically connected to the second relay through its P1.2 / ADC2 port.

[0063] Please refer to this section. Figure 5 and Figure 6 As shown, the serial communication circuit includes chip U1, capacitors C1, C2, C3, C4, C5, transient voltage suppressor diodes TVS1 and TVS2. Chip U1 is specifically model SP3232EEN. The C1+ port of chip U1 is connected to its C1- port via capacitor C1. The C2+ port of chip U1 is connected to its C2- port via capacitor C4. The VCC port of chip U1 is connected to the power supply voltage, which is also grounded via capacitor C2. The Vs+ port of chip U1 is grounded via capacitor C3. The Vs- port of chip U1 is grounded via capacitor C5. The GND port of chip U1 is grounded.

[0064] The T2OUT port of the chip U1 is grounded through the transient suppression diode TVS1, and the R2IN port of the chip U1 is grounded through the transient suppression diode TVS2. The T2OUT port and the R2IN port are connected to an external PC to receive control commands issued by the external PC, such as the first preset signal, the second preset signal, the third preset signal, or the fourth preset signal.

[0065] The TxD / P3.1 port of chip U2 is connected to the T2IN port of chip U1, and the RxD / P3.0 port of chip U2 is connected to the R2OUT port of chip U1 to realize communication between chip U1 and chip U2.

[0066] Please refer to this section. Figure 8 As shown, the specific structure of the status monitoring unit includes an optical coupler U3, wherein,

[0067] The anode of the optocoupler U3 is connected to a power supply voltage via resistor R1, and the cathode of the optocoupler U3 is connected to the explosion-proof microphone or switching terminal. In this example, please refer to... Figure 3As shown, the cathode of the optocoupler U3 is connected to the positive terminal of the switching terminal, the emitter of the optocoupler U3 is grounded, and the emitter of the optocoupler is connected to the power supply voltage and the main control unit respectively. Specifically, the emitter sends the SG1 detection signal to the P1.4 / SS / ADC4 port of the chip U2 in the main control unit.

[0068] By using an optocoupler, the signal between the explosion-proof microphone and the switching terminal is isolated from the signal between the main control unit, thus protecting the main control unit.

[0069] Furthermore, this circuit also includes resistor R2 and switching transistor Q1, wherein,

[0070] The main control unit is connected to the control terminal of the switching transistor Q1 through the resistor R2, and the power supply voltage is grounded sequentially through the other two ends of the switching transistor Q1 and the coil of the first relay.

[0071] By using the switching transistor Q1, when it receives a low-level signal or a high-level signal from the main control unit at its control terminal, its other two terminals can be turned on or off, so as to control the energization of the coil of the first relay and make the first relay energized or de-energized.

[0072] Specifically, please refer to this section. Figure 7 As shown, the switching transistor Q1 is a PNP transistor Q1. The P0.2 port of the chip U2 in the main control unit is connected to the base of the PNP transistor Q1 through the resistor R2. The power supply voltage is grounded through the emitter, collector and coil of the PNP transistor Q1 in sequence.

[0073] The main control unit is configured to transmit relevant control signals to chip U2 when chip U1 receives a first preset signal or a third preset signal from the PC, and then chip U2 configures the base of the PNP transistor Q1 to a low level through its P0.2 port; when chip U1 receives a second preset signal from the PC, it transmits relevant control signals to chip U2, and then chip U2 configures the base of the PNP transistor Q1 to a high level through its P0.2 port.

[0074] Specifically, this circuit also includes a freewheeling diode D1, which is connected in parallel with the coil of the first relay. In this embodiment, the collector of the PNP transistor Q1 is grounded through the cathode and anode of the freewheeling diode D1 in sequence.

[0075] By setting the freewheeling diode D1, the coil of the first relay can be discharged when it changes from being energized to being de-energized.

[0076] Specifically, this circuit also includes a light-emitting diode LED1 and a resistor R3. The anode of the light-emitting diode LED1 is connected to the collector of the PNP transistor Q1 through the resistor R3, and the cathode of the light-emitting diode LED1 is grounded.

[0077] The coil status of the first relay can be monitored by setting LED1.

[0078] Furthermore, this circuit also includes resistor R5, PNP transistor Q2, and freewheeling diode D2, wherein,

[0079] The P1.2 / ADC2 port of the chip U2 of the main control unit is connected to the base of the PNP transistor Q2 through the resistor R5, and the power supply voltage is grounded in sequence through the emitter, collector and coil of the PNP transistor Q2 and the second relay.

[0080] The main control unit is configured to transmit relevant control signals to chip U2 when chip U1 receives a third preset signal from the PC, and then chip U2 configures the base of the PNP transistor Q2 to a low level through its P1.2 / ADC2 port; when chip U1 receives a first preset signal or a second preset signal from the PC, it transmits relevant control signals to chip U2, and then chip U2 configures the base of the PNP transistor Q2 to a high level through its P1.2 / ADC2 port.

[0081] The freewheeling diode D2 is connected in parallel with the coil of the second relay. In this embodiment, the collector of the PNP transistor Q2 is grounded in sequence through the cathode and anode of the freewheeling diode D2.

[0082] Specifically, this circuit also includes a light-emitting diode LED2 and a resistor R6. The anode of the light-emitting diode LED2 is connected to the collector of the PNP transistor Q2 through the resistor R6, and the cathode of the light-emitting diode LED2 is grounded.

[0083] The specific working process of this utility model is as follows, please refer to [here]. Figure 4 As shown:

[0084] When in automatic switching mode:

[0085] When the explosion-proof microphone is suspended, the positive terminal of the switching terminal will generate a low level of 0V; when the explosion-proof microphone is picked up, the positive terminal of the switching terminal will generate a high level of 5V. The corresponding microphone status acquisition unit acquires the above level at the cathode of its optocoupler. When the cathode of the optocoupler acquires a high level, the optocoupler is disconnected. At this time, the collector of the optocoupler outputs an SG1 signal, which outputs a low level to the P0.2 port of chip U2. Then, chip U2 feeds back the microphone status to the PC through chip U1 in the serial communication circuit. When the cathode of the optocoupler acquires a low level, the optocoupler is turned on. At this time, the collector of the optocoupler outputs an SG1 signal, which outputs a high level to the P0.2 port of chip U2. Chip U2 feeds back the microphone status to the PC through chip U1 in the serial communication circuit.

[0086] When in microphone mode:

[0087] At this time, the positive terminal of the switching terminal is always at a high level of 5V; corresponding to the microphone status acquisition unit, the negative terminal of the optocoupler acquires a high level, the optocoupler is disconnected, and the collector terminal of the optocoupler sends an SG1 signal to output a low level to the P0.2 port of chip U2. Then, chip U2 feeds back the current microphone status (the microphone is always on) to the PC through chip U1 in the serial communication circuit.

[0088] When in machine audio mode:

[0089] The positive terminal of the switching terminal is always at a low level of 0V; corresponding to the microphone status acquisition unit, the negative terminal of the optocoupler acquires a low level, and the optocoupler is turned on. At this time, the collector terminal of the optocoupler sends an SG1 signal to output a high level to the P0.2 port of chip U2. Chip U2 feeds back the current microphone status (the microphone is in a disconnected state) to the PC through chip U1 in the serial communication circuit.

[0090] In other words, in automatic switching mode, the PC sends serial port commands to the main control unit to monitor the level changes of the explosion-proof microphone in real time, thereby realizing the status monitoring of the explosion-proof microphone;

[0091] When the host is in microphone mode or device speaker mode, the microphone status is either always connected or disconnected, and it will not return to microphone status in either of these two states.

[0092] The controllability of the three modes is achieved by switching the first and second relays on and off;

[0093] When a specific mode is needed, the PC sends instructions to the chip U1 via serial port to freely switch between the three modes.

[0094] Specifically, please refer to Table 1:

[0095] When it is necessary to switch to automatic switching mode, the PC sends a serial port command with a first preset signal to the chip U2 through the chip U1. The control signal SG2 output from the P0.2 port of the chip U2 becomes low and the control signal SG3 becomes high. At this time, the PNP transistor Q1 is turned on and the PNP transistor Q2 is turned off. The first relay is energized and the second relay is de-energized, thus realizing the automatic switching mode.

[0096] When it is necessary to switch to microphone mode, the PC sends a serial port command with a second preset signal to chip U2 through chip U1. The control signal SG2 output from port P0.2 of chip U2 becomes high level, and the control signal SG3 becomes high level. At this time, PNP transistor Q1 and PNP transistor Q2 are cut off, the first relay is disconnected, and the second relay is disconnected, thus realizing microphone mode.

[0097] When it is necessary to switch to the machine audio mode, the PC sends a serial port command with a third preset signal to the chip U2 through the chip U1. The control signal SG2 output from the P0.2 port of the chip U2 becomes low and the control signal SG3 becomes low. At this time, the PNP transistor Q1 and the PNP transistor Q2 are turned on, one relay is energized, and the second relay is energized, realizing the machine audio mode.

[0098] Table 1 Mode Switching Logic Table

[0099] Audio switcher mode Relay 1 Relay 2 Microphone mode disconnect disconnect Machine audio mode suction suction Automatic switching mode suction disconnect

[0100] With the above structure, this circuit can effectively solve the current gaps in the field of financial self-service machines, such as the uncontrollability of audio switchers and the inability to query their status.

[0101] This utility model also provides an audio switcher device for financial self-service machines, including a controllable audio switching circuit as described above.

[0102] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0103] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0104] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0105] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A controllable audio switching circuit, characterized in that, include: The system includes an explosion-proof microphone, a first relay, a second relay, a main control unit, a switching terminal, and a machine audio system connected to the switching terminal. One end of the explosion-proof microphone is connected to one end of the switching terminal via the first relay, and the other end of the switching terminal is connected to the other end of the explosion-proof microphone. The second relay is connected in parallel with the switching terminal. The main control unit is electrically connected to the first relay and the second relay respectively, so as to control the first relay and the second relay to engage or disengage.

2. The controllable audio switching circuit according to claim 1, characterized in that, The main control unit is configured as follows: Upon receiving a first preset signal, the first relay is controlled to engage, and the second relay is controlled to disengage. Upon receiving a second preset signal, the first relay is controlled to disconnect, and the second relay is controlled to disconnect. Upon receiving a third preset signal, the first relay is controlled to engage, and the second relay is controlled to engage.

3. The controllable audio switching circuit according to claim 2, characterized in that, This circuit also includes a status monitoring unit; One end of the status monitoring unit is connected to the explosion-proof microphone or the switching terminal, and the other end of the status monitoring unit is connected to the main control unit to transmit the connection status between the explosion-proof microphone and the switching terminal to the main control unit.

4. The controllable audio switching circuit according to claim 3, characterized in that, The status monitoring unit includes an optical coupler, wherein... The anode of the optical coupler is connected to the power supply voltage, the cathode of the optical coupler is connected to the explosion-proof microphone or switching terminal, the transmitter of the optical coupler is grounded, and the transmitter of the optical coupler is connected to the power supply voltage and the main control unit respectively.

5. A controllable audio switching circuit according to claim 2, characterized in that, This circuit also includes resistor R2 and switching transistor Q1, wherein, The main control unit is connected to the control terminal of the switching transistor Q1 through the resistor R2, and the power supply voltage is grounded sequentially through the other two ends of the switching transistor Q1 and the coil of the first relay.

6. The controllable audio switching circuit according to claim 5, characterized in that, The switching transistor Q1 is a PNP transistor Q1. The main control unit is connected to the base of the PNP transistor Q1 through the resistor R2. The power supply voltage is grounded through the emitter, collector and coil of the PNP transistor Q1 in sequence. The main control unit is configured to set the base of the PNP transistor Q1 to a low level when it receives a first preset signal or a third preset signal; and to set the base of the PNP transistor Q1 to a high level when it receives a second preset signal.

7. A controllable audio switching circuit according to claim 6, characterized in that, This circuit also includes a freewheeling diode D1, which is connected in parallel with the coil of the first relay.

8. A controllable audio switching circuit according to claim 7, characterized in that, This circuit also includes a light-emitting diode LED1 and a resistor R3. The anode of the light-emitting diode LED1 is connected to the collector of the PNP transistor Q1 through the resistor R3, and the cathode of the light-emitting diode LED1 is grounded.

9. A controllable audio switching circuit according to claim 2, characterized in that, This circuit also includes resistor R5, PNP transistor Q2, and freewheeling diode D2, wherein... The main control unit is connected to the base of the PNP transistor Q2 through the resistor R5, and the power supply voltage is grounded in sequence through the emitter, collector and coil of the PNP transistor Q2 and the second relay. The main control unit is configured to set the base of the PNP transistor Q2 to a low level when it receives a third preset signal; and to set the base of the PNP transistor Q2 to a high level when it receives a first preset signal or a second preset signal. The freewheeling diode D2 is connected in parallel with the coil of the second relay.

10. An audio switcher device for financial self-service machines, characterized in that, Includes a controllable audio switching circuit as described in any one of claims 1 to 9.

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