JPS6365185B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an intercom system, and in particular,
This invention relates to an intercom system that improves the convenience of use by providing a terminal with a loudspeaker reception function.

[Prior Art] A typical telephone exchange system is generally configured with a so-called centralized wiring network in which two wires connect terminals and the exchange. This is an advantage because it is relatively easy to install, but recently there has been an increasing demand for free-hand operated public address terminals due to the inconvenience of telephone-based communication.

Currently, the mainstream wiring network for public address exchange systems is a four-wire centralized system, but if it were possible to use the two-wire centralized system described above, it would be even more convenient. However, 2
Since it would be technically difficult to carry out loudspeaker control using a wire system, one method is to make the power supply for operating the loudspeaker amplifier self-supplied on the terminal side, and control the connection between the exchange and the terminal at the telephone level. A method can be considered that achieves a two-wire public address function by doing so.

Incidentally, since exchanges and terminals are usually installed quite far apart, the power line systems are often different. Therefore, when power is supplied from the exchange all at once, if the power to the exchange is cut off, all functions will stop, and the abnormality will be obvious. In addition, equipment such as an emergency power supply may also be considered if necessary. However, it is economically difficult to manage these for each terminal. On the other hand, as a self-sufficient power source, batteries and the like are not practical due to economic considerations such as maintenance, and therefore, they are used as small DC power supplies by replacing general commercial AC power lines with low-voltage DC.

[Problems to be Solved by the Invention] Under these circumstances, in the terminal system having the two-wire public address function, if the self-sufficient power supply on the terminal side is cut off (the power line is disconnected,
(wire disconnection or power outage, etc.), not only telephone calls but also the calling function will stop. Moreover, since the caller cannot detect these abnormalities, it is extremely inconvenient to use the system.

[Object of the Invention] The present invention has been made in order to solve the above-mentioned difficulties, and aims to provide an intercom system that can automatically supply power to an intercom exchange when the self-sufficient power supply on the terminal side is cut off. It is.

[Means for Solving the Problems] In order to achieve such an object, the intercom system according to the present invention includes an intercom exchange and a telephone having a function of receiving a calling signal sent from the intercom exchange and a telephone function. a telephone terminal having a talking part and a loudspeaker receiving part that is equipped with a self-sufficient power supply and becomes in a receiving state by receiving a calling signal sent from the intercom exchange;
The telephone conversation unit includes a calling sound body that becomes active upon receiving a calling signal sent from the intercom exchange, and the loudspeaker receiver includes a speaker;
an oscillator that sends a signal notifying an incoming call to the speaker for a certain period of time when the ringing signal is received; switching means for making the oscillator active, deactivating the oscillator and deactivating the calling sound body of the telephone communication unit when the self-sufficient power source is cut off and the calling signal is received; It is something.

[Embodiments of the Invention] Preferred embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, a telephone type intercom terminal 1 and an intercom exchange (not shown) are connected by two lines l ₁ and l ₂ . In Figure 2, I ₁
represents the DC current level of each line during a call, and _I2 represents the DC current level of each line when a call is received. These line DC currents are determined by the resistance of terminal 1 on lines l ₁ and l ₂ during a call and when a call is received, respectively, and in order to extend the communication distance, level I ₁ is determined by level I ₂
For example, by default the former is
7.2mA, the latter 3.6mA.

As shown in FIG. 1, a telephone type intercom terminal 1 comprises a telephone conversation section 2 and a loudspeaker receiving section 3 which is supplied with a self-contained power source (not shown) via lines _l3 and _l4 .

H ₁ , H ₂ and H ₃ of the telephone communication section 2 are switch switches linked to the handsets T and R.

The movable parts of the switch switches H ₁ , H ₂ and H ₃ are respectively connected to the input of the amplifier A ₁ , the output of the hybrid circuit HB and the line l ₁ . Contacts a and b of the switch _H1 are connected to a microphone M and a transmitter T, respectively, and the output section of the amplifier _A1 is connected to the input section of the hybrid circuit HB. Contacts c and d of the switch _H2 are connected to the primary coil of the transformer L and the receiver R, respectively.

Further, the contact f of the switch _H3 is connected to the amplifier _A1 via the collector of the transistor _Q1 , the diode _D1 , the hybrid circuit, and the resistor _R1 .
On the other hand, the contact e is connected to the emitter of the transistor _Q1 and the Zener diode ZD.

The base of the transistor Q ₁ is connected to the line l ₂ via a resistor R ₂ and a photocoupler P ₁ . A branch is formed of a diode D ₁ , a diode D ₂ in the opposite direction, a transistor Q ₂ and a Zener diode, and the connection point of the diodes D ₁ and D ₂ is connected to the line l ₂ via a resistor R ₃ . There is.
Transistor Q ₁ of telephone communication section 2, photocoupler
P ₁ and a transistor Q ₄ of the loudspeaker receiver 3, which will be described later.
The switching means is composed of photocoupler _P2 .

The collector of the transistor Q ₂ is connected via the capacitor C ₂ to the input of the amplifier A ₂ and via the resistor R ₄ to the power supply of the amplifier A ₂ , and the output of the amplifier A ₂ is applied to the calling sound body B. Note that C ₂ and C ₃ represent capacitors. Note that the amplifier A ₁ of the telephone communication section 2,
A ₂ operates the exchange power supply for the intercom.

The loudspeaker receiver 3 is composed of a transistor Q ₄ , a photocoupler P ₂ , a speaker SP, a loudspeaker amplifier A ₃ and an oscillator O.

In the loudspeaker receiver 3, between the lines _l3 and _l4, there are an oscillator O, a loudspeaker amplifier A3, and a loudspeaker amplifier _A3 , which sends a signal indicating an incoming call to the speaker SP via a transistor _Q4 .
Capacitor C ₆ is connected in parallel. The base of the transistor Q ₄ is connected to the line l ₄ through a resistor R ₉ , a photocoupler P ₂ and a Zener diode ZD
is connected to line l ₂ via resistor R ₆ and photocoupler P ₂ .

Also, line l ₃ is connected to resistor through transistor Q ₄
R ₅ is connected to line l ₄ via photocoupler P ₁ . The output of oscillator O is capacitor C ₄ , C ₅ and resistor
It is applied to the input of the loudspeaker amplifier A ₃ via an attenuation circuit formed by R ₇ , R ₈ , transistor Q ₃ and diode D ₃ . This attenuation circuit causes the output of the oscillator O to be sent to the speaker SP for a certain period of time to notify the speaker SP of an incoming call. Note that a speaker SP is connected to the output section of the loudspeaker amplifier _A3 .

[Operation of the Invention] Next, the operation of the circuit system configured as described above will be explained. FIG. 1 shows the standby state. Therefore, the switch switches H ₁ , H ₂ , and H ₃ are located at the control points a, c, and e, respectively.

When a call is received, the line DC current determined by the resistance of the terminal 1 to the lines l ₁ and l ₂ at the time of the call is at level I ₂ (FIG. 2). This level of current operates the amplifier A2 through a path consisting of the line _l1 , the contact e of the switch _H3 , the Zener diode ZD, _the transistor _Q2 , the resistor _R4 , the amplifier _A2 , and the line _l2 . Now, from the intercom exchange, line l ₁ ,
When the calling signal S ₂ is sent via l ₂ , the calling signal S ₂ is amplified by the amplifier A ₂ via the capacitor C ₂ and is broadcast by the calling sound body B. In this way, the telephone conversation section 2 has a calling function. Note that, before the line DC current is sent out when a call is received, almost no line DC current flows during standby.

However, at this time, photocoupler _P2 is turned on via Zener diode ZD and resistor _R6 , so
Here, when self-sufficient power is supplied to lines l ₃ and l ₄ , transistor Q 4 is turned on via resistor R ₉ , and at the same time power is turned on to loudspeaker amplifier A ₃ , the transistor Q ₄ is turned on via resistor R ₅ . In order to turn on photocoupler _P1 , transistor _Q1 turns on. As a result, the state is the same as if the transmitters T and R were picked up, and the resistance of the terminal during talking to the lines l ₁ and l ₂ becomes low, and the level I ₁ (Figure 2) is transmitted through the transistor Q ₁ . Line direct current flows during a call.
For this reason, diode D ₁ causes transistor Q ₂
becomes reverse biased, and intercom exchange power supply to amplifier _A2 is cut off, so that the above-mentioned call notification of telephone communication section 2 does not function. In other words, the calling function causes the oscillator O of the loudspeaker receiver 3 to oscillate, and the output is used to charge C ₄ and R ₈ in the charging circuit formed by the capacitor C ₄ , resistor R ₈ , transistor Q ₃ , and resistor R ₇ . The transistor _Q3 is switched with a time constant to create a percussive attenuation signal, which causes the speaker SP to sound via the loudspeaker amplifier _A3 . In addition,
Diode _D3 is in the charging circuit to discharge capacitor _C4 for next charging.
At this time, level I ₁ is set on the intercom exchange side.
is detected and control is performed to stop the ringing signal S ₂ , so the superimposition of the ringing signal S ₂ is eliminated, and by exchanging calls, the above-mentioned line DC current is added to the line DC current during a call, and the ringing signal S ₁ (Figure 2) are superimposed. That is, as mentioned above, since the transistor _Q1 is ON, power is supplied to the amplifier _A1 from the intercom exchange, and the transmission signal is transmitted by the microphone M to the hook switch.
Contact a of _H1 , amplifier _A1 , hybrid circuit HB,
Transistor Q ₁ , via contact e of switch H ₃ to line l ₁ , while the receive signal is routed to line l ₁ ,
Contact e of switch _H3 , transistor _Q1 ,
Speaker SP via hybrid circuit HB, contact c of switch _H2 , transformer L, and loudspeaker amplifier _A3 .
The sound becomes louder and louder. In this way,
When self-sufficient power is supplied to the loudspeaker receiver 3 of the telephone intercom terminal 1, the loudspeaker receiver automatically operates. Further, the receiver on the terminal side can perform the receiver function without operating the loudspeaker receiver 3.

Note that the current flowing through the transistor _Q4 is modulated by the audio voltage applied to the photocoupler _P2 via the resistor _R6 , but this modulated current is shunted by the capacitor _C6 .

When a call is received, if the self-sufficient power supply to lines L ₃ and L ₄ is cut off for some reason, photocoupler P ₂ will be turned ON, but transistor Q ₄ will be OFF, so that the self-sufficient power supply to the loudspeaker amplifier A ₃ will be interrupted. is not supplied and the photocoupler is connected via resistor R ₅ .
Since P ₁ remains OFF, transistor Q ₁
OFF is maintained, and when a call arrives at level I ₂ (Figure 2), the line DC current flows through line l ₁ , contact e of switch H ₃ , Zener diode ZD, and transistor.
Amplifier A ₂ is operated through a path consisting of Q ₂ , resistor R ₄ , amplifier A ₂ , and line l ₂ , and when a calling signal S ₂ is sent from the intercom exchange via lines l ₁ and l ₂ , a call is made. The signal S ₂ is amplified by the amplifier A ₂ via the capacitor C ₂ and then broadcast by the calling sound source B.

Next, if you pick up the transmitters T and R on the telephone side, the hook switches H ₁ , H ₂ , and H ₃ will connect to contacts b, d,
f respectively, a level _I1 line DC current flows through the contact f of the switch _H3 during a call, and the amplifier _A1 operates on the intercom exchange power supply. The transmission signal is sent from the transmitter T to the contact b of the switch _H1 , the amplifier _A1 , and the hybrid circuit.
HB, line via contact f of switch _H3
l1 , while the reception signal is sent to line _l1 , contact f of switch _H3 , hybrid circuit HB,
Contact d of switch H ₂ , handset R, line L ₂
Ring the receiver R using the route. In this case, the intercom switch detects level I ₁ and performs control to stop the ring signal S ₂ , so the ring signal
There is no superposition of S ₂ .

In this way, even when the self-sufficient power supply to the loudspeaker receiver 3 of the telephone intercom terminal 1 is cut off, the telephone conversation section 2 has the calling and conversation functions as a telephone intercom terminal.

It is obvious from the above description that even if self-sufficient power is supplied to the loudspeaker receiver 3, it is possible to make a normal telephone conversation by picking up the handset.

Additionally, although the circuits of the telephone conversation section 2 and the loudspeaker receiving section 3 are separated in terms of direct current, crosstalk is prevented by utilizing photocouplers P ₁ and P ₂ for this purpose.

[Effects of the Invention] As is clear from the above description, the intercom system of the present invention includes an intercom exchange, a telephone communication unit having a function of receiving a calling signal sent from the intercom exchange, and a telephone conversation function. , a telephone terminal having a self-sufficient power supply and a loudspeaker receiving unit that receives a calling signal sent from the intercom exchange and enters a receiving state;
The telephone conversation unit includes a calling sound body that becomes active upon receiving a calling signal sent from the intercom exchange, and the loudspeaker receiver includes a speaker;
an oscillator that sends a signal notifying an incoming call to the speaker for a certain period of time when the ringing signal is received; switching means for making the oscillator active, deactivating the oscillator when the self-supplied power source is cut off and receiving the calling signal, and deactivating the calling sound body of the telephone conversation section; Therefore, when the self-sufficient power supply to the loudspeaker receiving unit is cut off, power is automatically supplied to the intercom exchange,
Not only can abnormalities be detected, but also calls can be made through the telephone communication unit, making it extremely convenient to use and providing even greater safety from the perspective of ensuring communication.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the intercom system according to the present invention, and FIG. 2 is a graph showing the line DC current level during a call and a conversation between a telephone type intercom terminal and an intercom exchange. 1...Telephone type intercom terminal, 2...Telephone communication section, 3...Speech receiving section, _l1 , _l2 ...Line, B
... Calling sound body, O ... Oscillator, P ₁ , P ₂ ... Photo coupler (switching means), Q ₁ , Q ₄ ... Transistor (switching means), SP ... Speaker.

Claims (1)

[Claims] 1. An intercom exchange, a telephone communication part having a function of receiving a calling signal sent from the intercom exchange and a telephone call function, and a self-sufficient power supply, receiving the calling signal sent from the intercom exchange and making a call. In the intercom system equipped with a telephone terminal having a loudspeaker receiving section, the telephone calling section includes a calling sound body that becomes active upon receiving a calling signal sent from the intercom exchange, comprises a speaker, and an oscillator that sends a signal notifying an incoming call to the speaker for a certain period of time when receiving the calling signal, and when the self-sufficient power supply is supplied and the calling signal is received, switching that makes the calling sound body of the telephone conversation unit inactive and the oscillator active, and when the self-supplied power source is cut off and the calling signal is received, the oscillator is made inactive and the calling sound body of the telephone conversation unit is deactivated; An intercom system characterized by having a means.