JPS6317266B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a telephone system comprising a plurality of telephones configured to be connected to a central office line by a switch.

Some telephone systems of this type use telephones that are normally used for single-station telephone lines; , there is no extension calling function. Therefore, when an extension calling function is required, a contact intercom is usually installed or a calling-only device using a speaker is installed separately from the subscriber telephone. Yet another type of button telephone device is one in which the main device accommodates multiple key telephones and is used to make and answer calls to a central office line, as well as to make calls and mutual calls between key telephones using extensions. In some cases, a main device is required and a control line other than the extension telephone line is required, which has the disadvantage that the device becomes complicated and expensive.

The present invention makes it possible to make extension calls by voice, without requiring a main device such as a key telephone device, and without installing a separate intercom, by using a telephone circuit in which a simple control switch is added to an ordinary subscriber telephone. This provides a telephone system that allows for

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is an interconnection diagram of the telephone system of the present invention, where TEL ₁ , TEL ₂ , ...... TEL _o-1 , TEL _o are telephone circuits used in the present invention, and central office lines l ₁ , l ₂ and extensions _L3 and _L4 , respectively. A DC power supply _VB is connected between one of the central office lines _l2 and one of the extension lines _l3 .

FIG. 2 is a circuit diagram of an example of the telephone shown in FIG. _S1 , _S2 , and _S3 of the switch S are interlocked, and normally the b side of the contact is in a conductive state. _T2 of the communication circuit 1 is an input terminal, _T3 is a ground terminal, and _T1 is a transmitter input terminal.

Normally, the b side of the switch S is conductive, so the voice output from the caller is input from the _T1 terminal and output between the _T2 and _T3 terminals of the communication circuit 1, and this signal is _L1 ,
Output to _L2 terminal. Next, by pressing the switch S, the a side of each contact S ₁ , S ₂ , S ₃ becomes conductive, the DC loop between L ₁ and L ₂ is held by the holding circuit 3, and the DC power supply V _B is switched to L _{3 .} It is supplied to the communication circuit 1 from the terminal. The transmitter output from the _T1 terminal passes through the extension circuit 2 and is output from the output terminal to the _L2 and _L4 terminals.
Signals can be sent to other phones connected to the L ₂ and L ₄ terminals. Therefore, by pressing the switch S on the telephone, the office lines of the L ₁ and L ₂ terminals are put on hold by the hold circuit 3, a simultaneous voice call is made to the other telephones on the extension, and the handset is picked up by the other telephone. By doing so, calls from the central office line can be transferred.

Figure 3 shows that the negative side of the constant power supply _VB is not connected to the central office line _l2 , and only when the telephone is off-hook is connected to the central office line.
It is a connection diagram connected to _l2 by the l contact of the l relay.

Figure 4 shows the power supply _VB connected to each telephone TEL ₁ , TEL ₂ ,...
..., TEL _o-1 , is a connection diagram with distributed built-in TEL _o . In this case, _l2 is shared by the central office line and the extension line.

FIG. 5 is a connection diagram in which the speaker ground wire of FIG. 4 is not connected to the L2 terminal as shown in FIG _{. 2} , but is connected to the extension _L3 . As a result, extension terminal L ₃ is always
It is disconnected from the _L2 terminal, and the terminals _L3 and _L2 are connected only when the telephone is taken off-hook.
It is also possible to add an _S4 contact to the switch S and disconnect the telephone call circuit 1, extension calling circuit 2, and speaker ground wire _T3 from the switch _S4 contact _HS2 .

FIG. 6 is a block diagram of a telephone used in the present invention. Direct current is applied from the outside between L ₃ and L ₄ ,
The connections of each telephone set are as shown in FIG. When you pick up the handset on the telephone circuit, the switch contacts
HS ₁ and HS ₂ turn on and HS ₃ switches,
Speaker SP is disconnected. Next, switch S
When you press , first contact S ₁ (positioning) is at point b,
The point a is shorted, and the holding circuit 3 connects the terminals L ₁ and L ₂ with DC. If you press it further, point b and terminal
When the L ₁ interval is expired and you press it again, S ₂ , S ₃ , and S ₄ (non-selected) are cut off from point b and moved to point a. Therefore, the external DC power supply V _B between L ₃ and L ₄ is connected to the calling circuit 1 and the calling circuit 2, and the audio output from the handset is sent between terminals L ₃ and L ₄ and sent to the speaker SP of the other telephone. Output.

FIG. 7a is an example of the telephone circuit TEL ₁ , TEL ₂ , ...... TEL _o-1 , TEL _o used in the connection configuration example of FIG. 1, where L ₁ and L ₂ are office line terminals, and L ₃ , L ₄ is an extension terminal. N is a communication circuit, L is a coil, T is a transmitter, and R is a receiver. S is a non-locking push button switch, and the contacts S ₁ , S ₂ , S ₃ are interlocked. B is a bell, HS ₁ and HS ₂ are switch switches, D _i
is an impulse contact for dial pulse transmission, D _s
is a shunt contact that closes when the dial is in operation,
A is an amplifier serving as a calling circuit, SP is a speaker, R ₁ ,
R ₂ , R ₃ , R ₄ are resistors, C ₁ , C ₂ , C ₃ are capacitors,
D ₁ and D ₂ are diodes.

In this specific example, the contacts S ₁ , S ₂ , and S ₃ of the push-button switch S are normally closed on the b side, and in this state, outgoing and answering calls to the central office line are made.

Next, if you want to transfer the call to another telephone using the extension line while you are talking to the central office line, press the pushbutton switch S and connect the contacts S ₁ , S ₂ , and S ₃ to the a side. Line terminal L ₁ → Hook switch HS ₁ → Impulse contact D _i → A side of contact S ₁ → Resistor R ₁ → Station line terminal
At the same _time , a resistor R ₁ is connected between the office lines l ₁ and l ₂ in the route of [extension terminal L ₃ →
A side of contact S ₂ → diode D ₁ → resistor R ₂ → coil L → transmitter T → lower side of hook switch HS ₂ → station line terminal L ₂ ] from DC power supply V _B to transmitter T. Direct current flows. At the same time, a DC voltage is applied from the DC power supply V _B to the amplifier A through the path [extension terminal L ₃ → a side of contact S ₂ → diode D ₂ → amplifier A → lower side of switch HS ₂ → office line terminal L ₂ ]. is applied to put it into operation. Therefore, when a ringing voice is emitted toward the transmitter T, the audio output signal from the transmitter T is as follows: [Capacitor C ₁ → Division of resistors R ₃ and R ₄ → Amplifier A → Capacitor C ₂ → Contact A side of S ₃ → extension terminal
L ₄ →Other telephone →Extension terminal L ₂ →Hook switch
HS ₂ lower terminal] route to other telephones. In other phones, contacts S ₁ , S ₂ , S ₃ are all b
Because it is located on the side, the speaker SP will be emitted by the transmitted audio signal through the route [extension terminal L ₄ → speaker SP → upper side of switch HS ₂ → extension terminal L ₂ ].

Note that the diode D ₁ has a local current [local line terminal L ₂
→ Resistor R ₁ → Between a and b of shooting type switch contact S ₁ → Resistor R ₂ ] It is inserted in order to prevent it from flowing into the contact S ₂ and extension terminal L ₃ side. Further, a diode _D2 is inserted to prevent a reverse voltage from being applied to the amplifier A.

In the specific example shown in Figure 7a, since a DC power supply V _B is inserted between the office line and the extension line, the DC current from this DC power supply V _B may flow to the office line side due to a failure or some kind of mistake. It cannot be said that there is no possibility that direct current from the office line side will flow to the extension line side.

In order to eliminate such drawbacks, a specific example in which the necessary DC power source is separated from the central line side is shown in FIG. 7b. In this specific example, the switch S has contacts S ₁ , S ₂ ,
It has S ₃ and S ₄ , and the switch HS ₁ and HS ₂ have
HS ₃ is also added.

Telephone circuit TEL ₁ according to the specific example of FIG. 7b
~TEL _o is connected as shown in Figure 8, with extensions l ₃ and l ₄
A DC power supply V _B is connected between them. Coil L ₀ increases the AC impedance between extensions l ₃ and l ₄ ,
Extensions _l3 and _l4 are inserted so that the calling voice signal is transmitted without significant attenuation.

In the specific example shown in FIG. 7b, in the normal state, the contacts S ₁ , S ₂ , S ₃ , and S ₄ of the switch S are in the state of contact on the b side, and in this state, outgoing calls and answering calls to the central office line can be made. will be carried out.

Next, when you want to transfer the call to another telephone using an extension while talking to the central office line, press the pushbutton switch S and make the contacts S ₁ , S ₂ , S ₃ , and S ₄ close to the a side. Station line terminal L ₁ → A side of switch S ₁ → Resistor R ₁ →
Connect the office line via the route of the switch HS ₂ → office line terminal L ₂ ].
Connect a resistor R ₁ between l ₁ and l ₂ to hold the central office line, and at the same time connect [extension terminal L ₃ → hook switch HS ₃
lower side of coil L _A → resistor R ₁₃ → a side of contact S ₄ → impulse contact D _i → coil L → transmitter T → a side of contact S ₂ → extension terminal L ₄ ]. Direct current flows from V _B to the transmitter T. At the same time, [Internal terminal L ₃ → Lower side of hook switch HS ₃ → Coil L _A
→ A side of contact S ₃ → Amplifier A (calling circuit) → Extension terminal L ₄ ] A DC voltage is applied from the DC power supply V _B to the calling circuit (amplifier A) to put it into an operating state. Therefore, if a calling voice is emitted toward the transmitter T, the audio output signal from the transmitter T is
[Coil L → Impulse contact D _i → A side of contact S ₄ →
Capacitor C ₁ → Division of resistors R ₁₁ and R ₁₂ → Calling circuit (amplifier A) → Capacitor C ₂ → Lower side of switch HS ₃ → Extension terminal L ₃ → Other telephone → Extension terminal L ₄ → Contact S ₂ a route] to other telephones. On other phones, the switch
Since HS ₃ is not switched, the speaker SP will be sounded by the transmitted audio signal through the path [extension terminal L ₃ → upper side of the switch HS ₃ → capacitor C ₄ → speaker SP → extension terminal L ₄ ]. Become.

In the specific example of FIG. 7b, the coil L _A and the capacitor C ₃ are filters for preventing the voice signal on the extension L ₃ from being fed back to the calling circuit (amplifier A), and R ₁₄ and R ₁₅ are switch
Capacitors C ₃ , C ₄ due to switching by HS ₃
It is a resistance to prevent charging and discharging.
It has a value that is two or more orders of magnitude larger than the impedance of the speaker SP.

The connections shown in FIG. 8 can be changed as shown in FIG. Insert a relay H into the office line _L1 , activate it when a communication current flows between the office lines, and connect a DC power supply _VB between extensions _L3 and _L4 using the contact h of the relay H.
By igniting the light emitting element LED of each phone,
It is possible to display that one of the telephones is in use on a local line call.

Figure 10 shows a configuration in which a speaker is used to transmit the bell signal in the form of a tone instead of operating the bell of each telephone, since when many telephones are connected in a branch, it is not possible to operate all the bells with the bell signal of the station. This is an example. When a bell signal is applied between L ₁ and L ₂ , its DC output passes through transistor TR ₁ which operates a tone oscillator, and a tone signal is output onto the L ₃ and L ₄ lines.

Figure 11 is an example of a telephone circuit including an additional circuit when using a normal standard telephone circuit TEL.
This applies to the connection configuration shown in the figure. In this specific example, the standard telephone circuit TEL includes a telephone circuit including a transmitter and a handset _, and a dial circuit connected to _the office line side terminal L ₀₁ ,
It has a configuration connected to L ₀₂ . standard telephone circuit
The part excluding the TEL is an additional circuit, which includes office line terminals L ₁ and L ₂ and extension line terminals L ₃ and L ₄ . The actual difference from the circuit in FIG. 3 is that a relay _H1 is inserted between the station line terminals _L1 - _L01 , and its contact _h1a is inserted in series with the resistor _R1 of the hold circuit. Extension terminal L ₃ ,
Insert contact h _1b of relay H ₁ and relay H ₂ between L ₄ ,
The output of the calling circuit is switched by contact _h2 of relay _H2 . Also, relay
H ₁ is equipped with a capacitor C ₁₀ with a large capacity (for example, 470 μF) to delay the recovery of this relay H ₁ , and a diode D to prevent this relay H ₁ from interfering with instantaneous changes in the station line current. ₁₀ and _D11 are connected in parallel.

In the specific example shown in FIG. 11, the contacts S ₁ , S ₂ , S ₃ , and S ₄ of the push-button switch S are normally in the closed state on the b side, and in this state, outgoing calls and answering calls to the central office line can be made. It is done. At this time, [office line terminal L ₁ → relay H ₁ → contact S ₄ b side → terminal L ₀₁ → hook switch contact HS ₁ → standard telephone circuit TEL → hook switch contact HS ₂ → terminal L ₀₂ → contact S ₂ b of
side → station line terminal L ₂ ], relay H ₁ operates,
The contact points h _1a and h _1b are contacts. Therefore, relay H ₂
also operates, and contact _h2 is switched to the a side.

Next, when you want to transfer the call to another telephone by extension while talking to the central office line, press the push button switch S and make the a side of each contact S ₁ , S ₂ , S ₃ , S ₄ close. Although the operating current path of the relay H ₁ is cut off, the accumulated charge in the capacitor C ₁₀ causes the relay H ₁ to
is held for a while (it can be adjusted sufficiently for about 10 seconds), so that [station line terminal L ₁ → a side of contact S ₁ → resistor R → contact h _1a (contact) → station line terminal L ₂ ] At the same time as placing a hold on the central office line in the route, [Extension terminal L ₃ → contact
A voltage is applied from the DC power supply V _B to the amplifier A through the path: a side of h ₂ → coil L _A → a side of contact S ₃ → calling circuit (amplifier A) → extension terminal L ₄ ], and amplifier A operates. state. Also, [extension terminal L ₃ → contact
A side of h ₂ → Coil L _A → Diode D ₁ → Resistor R ₂ →
A side of contact S ₄ → terminal L ₀₁ → hook switch contact
Current flows through the standard telephone circuit TEL through the following path: HS ₁ → standard telephone circuit TEL → switch contact HS ₂ → terminal L ₀₂ → a side of switch S ₂ → extension terminal L ₄ ]. Therefore, if you emit a ringing voice to the transmitter in the standard telephone circuit TEL, the standard telephone circuit
The audio output signal from TEL is as follows: [Hook switch contact HS ₁ → terminal L ₀₁ → contact S ₄ a side → capacitor
C ₁ → Division of resistors R ₁₁ and R ₁₂ → Calling circuit (amplifier A) → Capacitor C ₂ → A side of contact h ₂ → Extension terminal
L ₃ → Other telephone → Extension terminal L ₄ → A side of contact S ₂ →
The signal is sent to other telephones via the path of terminal L ₀₂ → switch contact HS ₂ ]. In other telephones, the switch _is not switched _, so relay _H1 does not operate, and therefore relay _H2 does _not operate. SP→extension terminal L ₄ ] route,
The speaker SP will be emitted by the transmitted audio signal. With other telephones, if you pick up the handset in response to this ringing signal, you can talk to the central office line.

If such an additional circuit system as shown in FIG. 11 is adopted, the same functions and effects can be obtained by connecting a commonly used standard telephone without adding any mechanism.

As explained in detail above, the telephone system of the present invention has a simple circuit configuration that allows the function of placing calls on hold on the central office line and calling all extensions at once without impairing the functions of making and answering calls to the central office line. Therefore, the practical effect is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a connection diagram showing an embodiment of the present invention, FIG. 2 is a connection diagram including blocks showing an example of a telephone circuit used in the embodiment of FIG. 1, and FIGS. 3, 4, and 5. is a connection diagram showing another embodiment of the present invention, FIG. 6 is a connection diagram including blocks showing another example of a telephone circuit used in the present invention, and FIG. 7a is a specific circuit of the configuration example of FIG. 2. Example diagrams, FIG. 7b is a concrete circuit example diagram of the configuration example of FIG. 6, and FIGS. 8, 9, and 10 are implementations of the present invention using the telephone circuits of FIGS. 6 and 7b. An exemplary connection diagram, FIG. 11, is a specific circuit example in which the standard telephone circuit is configured by adding additional circuits so as to be applied to the embodiments of FIGS. 8, 9, and 10. l ₁ , l ₂ ... office line, l ₃ , l ₄ ... extension line, L ₁ , L ₂ ... office line terminal, L ₃ , L ₄ ... extension line terminal, HS ₁ , HS ₂ ,
HS ₃ , HS ₄ ... Switch contacts, S ₁ , S ₂ ,
S ₃ , S ₄ ... Non-locking switch contacts, V _B ...
DC power supply.

Claims (1)

[Claims] 1. A plurality of telephones are branch-connected to a pair of central office lines and a pair of extension lines, and each telephone has a function in which, when placed on hold for the central office line, the telephone circuit is switched from the central office line to the extension line. 1. A telephone system comprising: a control means for making it possible to make a simultaneous voice call to other telephones via the extension line using a transmitter of the telephone circuit.