JP4328186B2 - Intercom device - Google Patents

Description

  The present invention relates to an interphone device, and more particularly to an interphone device that can prevent a click sound from being output from an entrance cordless handset.

  Conventionally, as this type of intercom device, there has been provided a master unit installed in a living room of a house, and an entrance slave unit connected to the master unit via a transmission path and installed at the entrance of the house. The call is detected by the call detection circuit of the parent device by operating the call button, and the call circuit of the entrance child device (hereinafter referred to as “child device call circuit”) and the call circuit of the parent device (hereinafter referred to as “parent phone call”) are switched by the relay. A circuit that makes a call between two circuits is known (for example, see Patent Document 1).

  Here, the master unit is a call detection system power supply circuit that supplies a call detection system voltage to the entrance slave unit via a call detection circuit and a relay at the time of standby and detection of a call, and a call detection system voltage at the time of a call. A communication system power supply circuit for supplying different communication system voltages to the entrance unit via a communication circuit and a relay, and the entrance unit detects a voltage supplied from the base unit, and a voltage detection circuit And a power supply circuit that supplies power to the call circuit when a call system voltage from the call system power supply circuit is detected.

  According to such an intercom device, it is possible to supply power to the communication circuit of the entrance slave unit only during the conversation between the master unit and the entrance slave unit, to minimize power consumption and to save energy. Can be achieved.

  By the way, in the intercom apparatus having such a configuration, as described below, the click sound from the front door unit due to the change in the DC voltage of the transmission path at the start or end of the call between the front door unit and the main unit. There was a difficulty of outputting. That is, at the start of a call, as shown in FIG. 7, the DC voltage of the transmission line rapidly rises from about 8V at the time of standby to about 15V at the time of the call, and a threshold value (about 10V) in the middle of this. In this case, the entrance cordless handset transitions from a standby state to a talking state in which the handset talker circuit is opened, but the DC voltage of the transmission line still increases after the transition to about 15 V during the call (see section A), and its displacement There is a problem that an unpleasant buzzing sound (hereinafter referred to as “click sound”) is output from the speaker of the front door unit as an audio output. At the end of the call, the DC voltage of the transmission line drops from about 15 V during the call to about 8 V during the standby, and the entrance cordless handset waits from the call with a certain threshold (about 10 V). Transitions to the reception state, but does not immediately transition to the standby state even if the threshold value is exceeded, and the handset communication circuit operates for a while, and the displacement of the DC voltage of the transmission line at this time (see part B) There is a drawback that a click sound is output from the speaker of the entrance cordless handset as an audio output.

  As described above, in the conventional intercom device, at the start or end of the call between the front door unit and the main unit, a click sound is output from the front door unit due to a change in the DC voltage of the transmission path, and thus high quality. The intercom device cannot be provided.

JP 2001-211262 (paragraph numbers “0011” and “0012”, FIG. 1)

  The present invention has been made to solve the above-described problems, and a click sound is output from the front door unit even when the DC voltage of the transmission line changes at the start or end of a call between the front door unit and the main unit. The purpose is to provide a high quality intercom device.

The intercom apparatus according to the present invention includes a parent device provided in a living room of a house, and a power supply supplied from a parent device power supply circuit provided at the entrance of the house via a child device power stabilization circuit, and a child device communication circuit via a transmission line. The main unit switches the DC voltage of the transmission line between standby and call, and the front unit detects the DC voltage of the transmission line and detects the direct current during standby. An interphone device that turns off a slave unit power stabilization circuit and a slave unit call circuit when detecting a voltage, and turns on a slave unit power source stabilization circuit and a slave unit call circuit when detecting a DC voltage during a call, The entrance cordless handset detects the voltage between the input and output of the handset impedance upper circuit and the handset impedance upper circuit to receive the DC voltage from the base power supply circuit while taking the AC impedance viewed from the transmission line high. Slave phone call circuit Chute to those with a mute timing detection circuit for click sound from the entrance door station is prevented from outputting.

  According to the intercom device of the present invention, the DC voltage of the transmission line is changed by muting the slave unit communication circuit of the entrance slave unit using the mute signal at the start or end of the call between the entrance slave unit and the master unit. Even so, it is possible to prevent the click sound from being output from the entrance cordless handset, and thus to provide a high quality intercom device.

  Hereinafter, a preferred embodiment to which an interphone device of the present invention is applied will be described in detail with reference to the drawings. Here, FIG. 1 is a block diagram showing an embodiment of the intercom apparatus of the present invention, and FIG. 2 is an explanatory diagram showing an example of a change in the DC voltage level of the transmission line in the embodiment.

  In FIG. 1, the intercom apparatus of the present invention includes an entrance cordless handset 1 provided at the entrance of a house and a base unit 2 provided in a living room of the house. The base unit 2 is connected to the entrance via a transmission line L. It is connected to the slave unit 1.

  The front cordless handset 1 includes a handset power supply stabilization circuit 11, a handset impedance upper circuit 12, a mute signal detection circuit 13, a handset communication circuit 14, a speaker 15, a microphone 16, a DC voltage detection circuit 17, and a call button 18. (Circuit). Here, handset power supply stabilization circuit 11 is connected to handset impedance upper circuit 12 and DC voltage detection circuit 17, and handset impedance upper circuit 12 and handset communication circuit 14 are connected to DC voltage detection circuit 17. ing. The handset impedance upper circuit 12, the mute signal detection circuit 13, the handset call circuit 14 and the call button 18 are connected to the transmission line L. The handset call circuit 14 includes a mute signal detection circuit 13, a speaker 15 and a microphone 16. Is connected.

  Base unit 2 includes relay 21, base unit impedance upper circuit 22, base unit impedance upper control circuit 23, base unit call circuit 24, handset 25, mute signal output circuit 26, call detection circuit 27, base unit power supply circuit 28, and CPU 29. Each part (circuit) is provided. Here, the relay 21 includes a common contact c, a break contact b, and a make contact m. The transmission line L, the mute signal output circuit 26, and the call detection circuit 27 are connected to the common contact c, and the break contact b is connected. Is connected to a base unit power supply circuit 28 via a high resistance R0, and a base unit impedance upper circuit 22, a base unit impedance upper control circuit 23, and a base unit call circuit 24 are connected to the make contact m. The CPU 29 is connected to the relay 21, the base unit impedance upper control circuit 23, the mute signal output circuit 26, the call detection circuit 27, and the base unit power supply circuit 28, and the base unit impedance upper circuit 22 includes the base unit impedance upper control circuit. 23 and a base unit power supply circuit 28, and a handset 25 is connected to the base unit call circuit 24, respectively.

Next, the operation of the intercom apparatus of the present invention configured as described above will be described. The visitor calls the master unit 2 by pressing the call button 18 of the front door 1 and emits a ringing tone from a master speaker (not shown), and the resident uses the handset 25 to talk to the visitor. When taken up, a communication path is formed between the slave unit call circuit 14 and the master unit call circuit 24, and voice signals can be transmitted / received via the call path, and a resident can talk with a visitor. When the handset 25 is returned to the base unit 2 to finish the operation, the point that the base unit 2 shifts to the standby state operates in the same manner as the conventional intercom apparatus, and thus detailed description is omitted. A description will be given centering on the operation of muting the handset communication circuit 14 of the front handset 1 at the start or end of a call between the handset 1 and the base 2.
[Example 1]
First, at the time of standby, the contact of the relay 21 is switched to the break contact b side. As a result, a standby voltage of about 8 V as shown in FIG. 2 is supplied to the entrance slave unit 1 from the base unit power supply circuit 28 via the high resistance R0 of about 2.2 kΩ, the relay 21 and the transmission line L. When the DC voltage of the transmission line L during such standby is detected by the DC voltage detection circuit 17, the slave unit power supply stabilization circuit 11 and the slave unit call circuit 14 are set to OFF.

  In such a state, when the visitor presses the call button 18 of the front door 1, a call signal is transmitted to the call detection circuit 27 via the transmission line L, and when the call signal is detected by the CPU 29, the CPU 29. As a result of this control, a mute signal (hereinafter referred to as “first mute signal”) is output from the mute signal output circuit 26, and this first mute signal is transmitted to the entrance terminal 1 via the transmission line L. When the first mute signal is detected by the mute signal detection circuit 13, the handset communication circuit 14 is muted for a certain time (for example, about 100 milliseconds) as shown in FIG.

  Here, while the handset communication circuit 14 is muted, the relay 21 is switched to the make contact m side. As a result, a call voltage of about 15 V as shown in FIG. 2 is supplied from the parent device power supply circuit 28 to the entrance child device 1 via the parent device impedance upper circuit 22, the relay 21, and the transmission line L. Then, the DC voltage of the transmission line L rises from the standby voltage (about 8V) to the call voltage (about 15V), and becomes a stable call voltage (DC voltage of about 15V). The mute is released, and it becomes possible to talk between the parent device 2 and the child device 1.

  Next, at the end of the talk, the resident returns the handset 25 to the main unit 2 and when the hook-on signal is detected by the CPU 29, the mute signal output circuit 26 controls the mute signal (hereinafter "second mute") under the control of the CPU 29. The second mute signal is transmitted to the entrance terminal 1 via the transmission line L. When the second mute signal is detected by the mute signal detection circuit 13, the handset communication circuit 14 is muted for a predetermined time (for example, about 100 milliseconds) as described above.

  Here, while the handset communication circuit 14 is muted, the relay 21 is switched to the break contact b side under the control of the CPU 29. As a result, a standby voltage (about 8 V) is supplied from the parent device power supply circuit 28 to the entrance child device 1 through the high resistance R0, the relay 21, and the transmission line L. Then, the slave unit call circuit 14 operates until the DC voltage of the transmission line L drops from the call voltage (about 15V) to the standby voltage (about 8V) and reaches a stable standby voltage (DC voltage of about 8V). Muted and after a certain period of time, the front door 1 returns to the standby state.

As described above, in the first embodiment, when switching from standby to call or from call to standby, the mute signal is output from the base unit 2 and the mute signal detection circuit 13 detects the mute signal. Thus, since the handset communication circuit 14 can be muted for a certain period of time, it is possible to prevent the click sound from being output from the front handset 1.
[Example 2]
FIG. 3 shows an embodiment in which the DC voltage level of the transmission line L is switched to three states: a standby state, a mute state, and a call state. In the figure, parts common to those in FIG. 2 are denoted by the same reference numerals and detailed description thereof is omitted.

  In this embodiment, the DC voltage supplied from the master unit power supply circuit 28 to the transmission line L by the control of the CPU 29 of the master unit 2 shown in FIG. 1 is “about 8V”, “about 12V”, and “about 15V”, respectively. Are switched to three states.

  In this embodiment, the DC voltage during standby of the transmission line L is about 8 V, as in the first embodiment. Then, the base unit power supply circuit 28 is controlled by the CPU 29 of the base unit 2, and the DC voltage of the transmission line L rises from about 8V in the standby state to about 15V in the telephone conversation state, but transitions from the standby state to the telephone communication state. On the way, the DC voltage of the transmission line L is set to an intermediate voltage (about 12 V) for a certain time (about 50 milliseconds).

  When such an intermediate voltage (DC voltage) of about 12 V is detected by the DC voltage detection circuit 17, the handset communication circuit 14 of the entrance handset 1 is muted for a certain time (about 100 milliseconds) and muted. In the meantime, the DC voltage of the transmission line L is raised to about 15V. As in the first embodiment, after the call voltage in a stable state (DC voltage of about 15 V) is reached, the mute of the handset call circuit 14 is released after a predetermined time has elapsed, and the base unit 2 and the handset 1 It becomes possible to make a phone call.

  Also at the end of the talk, as described above, the base unit 2 drops the DC voltage of the transmission line L from about 15V to about 12V, and the DC voltage detection circuit 17 detects the DC voltage of 12V as the intermediate voltage. Then, the handset communication circuit 14 is muted for a predetermined time (about 100 milliseconds), and the DC voltage of the transmission line L is lowered to about 8V while being muted. Then, handset communication circuit 14 is muted until the standby voltage in a stable state (DC voltage of about 8 V) is reached, and entrance slave unit 1 returns to the standby state after a predetermined time has elapsed.

As described above, in the second embodiment, the slave unit call circuit of the front cordless handset 1 is detected by detecting the intermediate voltage (for example, about 12 V) before switching from standby to call or from call to standby. Since 14 can be muted, it is possible to prevent the click sound from being output from the front door set 1.
[Example 3]
In this embodiment, as shown in FIG. 1, the AC impedance viewed from the transmission line L of the base unit impedance upper circuit 22 is set to a high value of about 700Ω, for example, by the control of the base unit impedance upper control circuit 23. Here, the conventional impedance upper circuit is always active, and a voltage at the time of a call is output from the impedance upper circuit. In this embodiment, the parent unit impedance upper circuit is controlled by the parent unit impedance upper control circuit 23. The voltage output from the circuit 22 can be gradually increased or gradually decreased. Specifically, as shown in FIG. 4, the DC voltage of the transmission line L when transitioning from standby to call can be gradually increased from about 8V to about 15V. The DC voltage of the transmission line L at the time of transition can be gradually lowered from about 15V to about 8V.

Therefore, in this embodiment, the base unit impedance upper control circuit 23 is provided, so that the output voltage of the base unit impedance upper circuit 22 is changed to the direct current of the transmission line from the standby time to the call time or from the call time to the standby time. The change in level can be controlled gently. As a result, even if the DC voltage of the transmission line L changes, it is possible to prevent the click sound from being output from the entrance unit 1.
[Example 4]
FIG. 5 is a block diagram showing another embodiment of the intercom apparatus of the present invention. In the figure, parts that are the same as those in FIG.

  In this embodiment, a mute timing detection circuit 19 is connected instead of the mute signal detection circuit 13 shown in FIG. 1, and a DC voltage from the parent device power supply circuit 28 is received by the child device impedance upper circuit 12. It is configured as follows.

  FIG. 6 is a block diagram showing an example of the handset impedance upper circuit 12 and the mute timing timing detection circuit 19 shown in FIG.

  In FIG. 6, the handset impedance upper circuit 12 includes first and second transistors TR1 and TR2, first to fourth resistors R1 to R4, and first and second capacitors C1 and C2. The mute timing detection circuit 19 includes third and fourth transistors TR3 and TR4, and fifth to ninth resistors R5 to R9. Here, the output side (DC voltage detection circuit 17 side) of the handset impedance upper circuit 12 is one side of each of the first, second, fourth, and fifth resistors R1, R2, R4, R5 and the first, The emitter of the first transistor TR1 is connected to one side of each of the second capacitors C1 and C2, and the other side of the first resistor R1 is connected to the other side of the first capacitor C1 and the second resistor R2. Is the base of the first transistor TR1 and the emitter of the second transistor TR2, and the other side of the fourth resistor R4 and the second capacitor C2 is one of the base of the second transistor TR2 and the third resistor R3. Each side is connected. In addition, the input side (transmission line L side) of the handset impedance upper circuit 12 is connected to the collectors of the first and second transistors TR1 and TR2, the other side of the third resistor R3, and the emitter of the third transistor TR3. The base of the fourth transistor TR4 is connected to the collector of the third transistor TR3 via the sixth and seventh resistors R6 and R7, respectively. Further, the emitter of the fourth transistor TR4 connected to the ground side is connected to the base of the fourth transistor TR4 via the eighth resistor R8, and the mute output point M is connected to the collector of the fourth transistor TR4. And is connected to the power supply voltage Vcc via a ninth resistor R9.

  In this embodiment, the AC impedance viewed from the transmission line 1 of the slave unit impedance upper circuit 12 is set to about 700Ω, for example, and the potential difference between the input and output of the slave unit impedance upper circuit 12 during a call is about 2V. Further, the mute output at the mute output point M is set at a low level so that the mute is canceled and the mute output is set at a high level. For this reason, during a call, the third transistor TR3 is turned on due to the potential difference between the input and output (about 2 V) in the slave unit impedance upper circuit 12, so that the fourth transistor TR4 is turned on. The mute output at the point M becomes low level and the mute is released.

  On the other hand, the DC potential of the transmission line fluctuates with the transition from the standby time to the call time, or from the call time to the standby time, and the potential difference between the input and output of the slave unit impedance upper circuit 12 rapidly decreases. If the potential difference between the input and output of the handset impedance upper circuit 12 becomes zero, the third transistor TR3 is turned off, and the fourth transistor TR4 is turned off. Therefore, the mute output at the mute output point M is high. It becomes a level and shows a mute state.

  As described above, in the fourth embodiment, the entrance slave unit 1 uses the mute timing detection circuit 19 to accurately set the voltage between the input and output of the slave unit impedance upper circuit 12 while taking the AC impedance viewed from the transmission line 1 high. Since it is possible to detect and mute the handset communication circuit 14 at an appropriate timing, it is possible to prevent the click sound from being output from the front handset 1.

  In the above-described embodiment, the DC voltage of the transmission line L is detected by the DC voltage detection circuit 17. However, the present invention is not limited to this, but the slave unit power supply stabilization circuit 11, the slave unit impedance upper circuit. A separate voltage detection circuit may be connected between the DC voltage detection circuit 12 and the DC voltage detection circuit 17, and the DC voltage of the transmission line L may be detected by this voltage detection circuit.

The block diagram which shows one Example of the intercom apparatus of this invention. Explanatory drawing which shows an example of the change of the DC voltage level of the transmission line in the intercom apparatus of this invention. Explanatory drawing which shows an example of the change of the DC voltage level of the transmission line in the intercom apparatus of this invention. Explanatory drawing which shows an example of the change of the DC voltage level of the transmission line in the intercom apparatus of this invention. The block diagram which shows the other Example of the intercom apparatus of this invention. The block diagram which shows an example of the subunit | mobile_unit impedance upper circuit and mute timing detection circuit which are shown in FIG. Explanatory drawing which shows an example of the change of the DC voltage level of the transmission line in the conventional intercom apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Entrance subunit | mobile_unit 11 ... Slave unit power supply stabilization circuit 12 ... Slave unit impedance upper circuit 13 ... Mute signal detection circuit 14 Slave unit call circuit 17 ... DC voltage detection circuit 19 ... -Mute timing detection circuit 2 ... Base unit 22 ... Base unit impedance upper circuit 23 ... Base unit impedance upper control circuit 26 ... Mute signal output circuit 28 ... Base unit power supply circuit 29 ... CPU
L: Transmission path

Claims (1)

Power is supplied from the master unit (2) provided in the residence room and the master unit power supply circuit (28) provided at the entrance of the residence via the slave unit power stabilization circuit (11), and is transmitted via the transmission line (L). A cordless handset communication circuit (14) and an entrance cordless handset (1) that communicates with the master phone, wherein the master phone switches the DC voltage of the transmission line between standby and talk time. Detects the DC voltage of the transmission line and turns off the slave unit power supply stabilization circuit and the slave unit call circuit when the standby DC voltage is detected, and detects the DC voltage during the call when the slave unit power source is detected. An intercom device that turns on a stabilization circuit and the handset communication circuit ,
The entrance cordless handset includes a handset impedance upper circuit (12) for receiving a DC voltage from the base unit power supply circuit while taking high AC impedance viewed from the transmission path, and a handset impedance upper circuit. An intercom apparatus comprising: a mute timing detection circuit (19) for detecting a voltage between input and output to mute the handset communication circuit to prevent a click sound from being output from the entrance handset.

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