JP2597458B2 - No-ringing terminal multi-connection circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a main terminal such as a telephone,
The present invention relates to a no-ringing terminal multi-connection circuit in which a plurality of juxtaposed terminals including a non-ringing terminal such as a telemeter are multi-connected to a communication line.

[0002]

2. Description of the Related Art FIG. 2 is a circuit diagram showing a configuration example of a conventional no-ringing terminal multi-connection circuit. The non-ringing terminal multi-connection circuit, the communication line 2, the main terminal 10 such as a telephone, the first to n-th features terminal 20 21 _to
0 _n of the two input terminals 21 ₁ , 22 _{1 to} 21 _n , 22 _n
Are multi-connected by a communication line . That is,
One communication line 1, through one input terminal of the main terminal 10
It is connected by signal lines, and the other communication line 2, the first through n cascaded provided in each hotel terminal 20 ₁ per to 20 _n
Via the detection circuit 40 ₁ to 40 _n busy are connected by communication lines to the other input terminal of the main terminal 10. Each busy detection circuit 40 ₁ to 40 _n performs detection main terminal 10 of whether or not busy, a circuit for supplying respectively the detected information to each hotel terminal 20 ₁ to 20 _n. Each hotel's terminal 20 ₁ ~20 _n is,
Detecting a polarity inversion detection circuit 23 ₁ ~ 23 _n to form a small current loop operates by polarity inversion signal from the not shown, connected to the communication line 1 and 2 exchange, a ringing signal from the communication line 1 and 2 Bell signal detection circuits 24 _{1 to} 24 _n ;
DP / which forms a current loop for transmitting dial pulse signal DP or push button signal PB at the time of transmission
PB sending circuits 25 _{1 to} 25 _n and current loop forming circuits 26 ₁ to 2 which form a current loop during communication to enable communication.
6 _n , each of which has two input terminals 21 ₁ , 22 _1.
To 21 _n , 22 _n . Further, each one of the input terminals 21 _{1 to} 21 _n and each current loop forming circuit 2
6 ₁ The ~ 26 _n output terminals of the transformer 27 ₁ ~ 27 _n are connected, respectively, to their output side of the transformers 27 ₁ ~ 27 _n of the hybrid circuits 28 ₁ ~ 28 _n and the modem 29
_1-29 through _n meter sensor 30 ₁ to 30 _n are respectively connected, each of which modem 29 _{1-29 n} and the control circuit 31 ₁ to 31 _n to the meter sensor 30 ₁ to 30 _n are connected ing. Each of the control circuits 31 _{1 to} 31 _n includes a polarity inversion detection circuit 23 ₁ to 23 _n and a bell signal detection circuit 24 ₁ to
Based on the output of the 24 _n, and busy detection circuit 40 ₁ to 40 _n, each DP / PB transmitting circuit 25 ₁ to 25 _n, and controls the operation of the current loop forming circuit 26 ₁ ~ 26 _n, each modem 29 ₁ ~ 29 _n, and performs transmission and reception of signals between the meter sensor 30 ₁ to 30 _n, a circuit for controlling the operation of the terminal, a central processing unit (hereinafter, CPU hereinafter) are each configured in such I have.

[0003] Next, transmission operation of the main terminal 10 (1), features the terminal 20 ₁ to 20 _n receive operation (2), and features the terminal 20
The transmission operation (3) for _{1 to} 20 _n will be described. (1) Operation when the main terminal 10 makes a call When the main terminal 10 such as a telephone makes a call, the loop current from the communication line 1 is turned off by hooking the main terminal 10 off, so that the communication line 1 → the main terminal 10 → the n busy detection circuit 40
_n → ... → Second busy detection circuit 40 ₂ → First busy detection circuit 40
₁ → Flow to communication line 2 and communication can be performed. At this time, the first
The n detection circuits 40 ₁ to 40 _n busy-detects the loop current, the control circuit 31 ₁ to the hotel's terminals 20 ₁ in to 20 _n
Since the information that the communication line is in use is transmitted to the first _n .
Outgoing to the n-th features terminal 20 ₁ to 20 _n is prevented. (2) in the main terminal 10 is on-hook state of operation telephone or the like when the hotel's terminal 20 ₁ to 20 _n performs reception, first to n-site terminal 20 ₁ to 20 _n are connected to the communication line 1 and 2 Upon detection by the by the polarity inversion detection circuit 23 ₁ ~ 23 _n polarity inversion signal from a not-shown switch was, the call signal from the exchange after activation signals received, thereby enabling communications. For example, the selection signal from the exchange, if the first features terminal 20 ₁ via the modem 29 ₁ is selected, the current loop forming circuit 26 ₁ is driven by the control circuit 31 _1, the loop from the communication line 1 The current is the communication line 1
→ The first internal terminal current loop forming circuit 26 ₁ → flows to the communication line 2, and a communication current loop is formed to enable communication. (3) If the hotel terminal 20 ₁ to 20 _n are operating features terminal 20 ₁ to 20 _n originates in the case of performing a call, the control circuit 31 ₁
To the DP / PB transmission circuit 25 ₁ driven by 31 _n .
By 25 _n, it can communicate by invoking the connected switching system to the communication line 2.

[0004]

However, the no-ringing terminal multi-connection circuit having the above configuration has the following problems. (A) when it is configured in the main terminal 10, for example, telephone, first to n-th features terminal 20 ₁ to 20 _n are first to each
Because it is connected to the main terminal 10 in parallel, including the (n-1) n-th busy detection circuit 40 _n across the busy detection circuit 40 ₁ ~40 _n-1, the hotel's terminal 20 ₁ to 20 DP / P in _n
When the B transmission circuits 25 _{1 to} 25 _n transmit, for example, the dial pulse signal DP, the potentials of the communication lines 1 and 2 greatly change. That is, the currents of the communication lines 1 and 2 are turned on and off. Therefore, the bell signal receiving circuit in the main terminal 10 responds, the bell rings, and a so-called resonance phenomenon occurs. (B) During the calling of the attached terminal, each DP / PB sending circuit 25
The terminal resistance of _{1 to} 25 _n is 300Ω or less according to the terminal installation standard (the actual value of the terminal equipment is about 50 to 200Ω), and the supply current from the exchange to the farthest subscriber is minimum 2
0 mA, the voltage that can be generated between the communication lines 1 and 2 of the farthest subscriber is 6 V or less (50 Ω in actual terminal equipment).
× 20mA = 1V to 200Ω × 20mA = 4V). However, about in each of the hotel's terminal 20 ₁ each ~20 _n 0.8~
Busy detection circuits 40 ₁ to 4 generating a potential drop of about 1 V
0 _n is required. For this reason, the number of devices that can be multi-connected is limited, or the subscriber area is limited (that is, the farthest subscriber can have only one co-located terminal). (C) In the circuit of FIG. 2, the use of the main terminal 10 such as a telephone is prioritized, and there is a problem that a priority function of an arbitrary terminal attached cannot be added. In order to solve the above-mentioned problems (a) to (c), the applicants of the present application have made the following improvements in the specification of Japanese Patent Application No. 4-291714 (hereinafter referred to as the prior proposal). Was.

In the above proposal, a main terminal capable of talking and having a calling function and a receiving function, a polarity inversion detecting circuit and a bell signal detecting circuit for obtaining information in the middle of an operation sequence required for communication, and an operation in the terminal. A plurality of juxtaposed terminals each comprising a no-ringing terminal having a control circuit for controlling the main terminal and a plurality of juxtaposed terminals, wherein the main terminal and the plurality of juxtaposed terminals are multi-connected to a communication line. Have taken. That is, the main terminal is connected to the communication line as the lowest terminal. And a plurality of switches provided on each of the co-located terminals for disconnecting lower terminals (terminals connected after the terminal performing the transmitting or receiving operation) after the used co-located terminal from the communication line; A busy detection circuit provided only on the terminal side for detecting whether or not the communication line is busy and providing the detection information to a control circuit in the lowermost attached terminal; and the main terminal provided in each of the attached terminals A plurality of off-hook detection circuits for detecting the off-hook state of the terminal and providing the detection information to a control circuit in each of the attached terminals, wherein the control circuit in each of the attached terminals controls each of the switches. I have.

When the no-ringing terminal multi-connection circuit is configured as described above, the switches provided on the side of each of the plurality of co-located terminals composed of no-ringing terminals such as telemeters are switched and controlled by the control circuit in each co-located terminal. Separate the lower terminal and the main terminal such as a telephone from the communication line. As a result, it is possible to prevent the resonance phenomenon of the main terminal at the time of calling the exchange by the dial pulse signal or the like at the time of transmission of the attached terminal. A busy detection circuit provided on the main terminal side such as a telephone detects the presence or absence of a busy line on a communication line, and sends the detection information to a control circuit in the lower terminal. An off-hook detection circuit provided in each of the attached terminals detects an off-hook state of the main terminal, and provides the detection information to a control circuit in each of the attached terminals, and the switching circuit is controlled by the control circuits. As a result, the load on the plurality of co-located terminals and the busy detection circuit as viewed from the communication line is reduced, and the number of multi-connected terminals and the subscriber area can be expanded. In the above proposal, the control circuits in each of the attached terminals are connected by a bus line for transmitting busy detection information and call detection information, and the polarity inversion detection circuit, the bell signal detection circuit, and the off-hook in each of the attached terminals are connected. The control circuit is provided with a priority function of any of the attached terminals or the main terminal based on each information of the detection circuit and the busy detection circuit and the operation state information such as the calling of the attached terminal. With such a configuration, the control circuit in each of the attached terminals transmits the busy information and the call detection information of the main terminal such as a telephone and the attached terminal to each other through a bus line, and the optional attached software or the like. A priority function can be added to a terminal or a main terminal. Therefore, in the above proposal, the problems of the prior art, such as resonance phenomenon of a main terminal such as a telephone at the time of calling a switchboard by a dial pulse signal at the time of calling of a co-located terminal, multi-connection number limitation or subscriber area limitation, And that the priority function of any additional terminal cannot be added. However, the following problems (i) to (iv) have occurred, and it has been difficult to provide a non-ringing terminal multi-connection circuit that is technically sufficiently satisfactory. (I) monitoring the state of the communication line independently for each terminal,
It is impossible to perform so-called autonomous control in which transmission and reception are performed asynchronously. That is, it is necessary to provide a bus line via a control circuit for displaying the status of the main terminal and the co-located terminal. Normally, since each terminal is installed at a physically separated position, this bus line extends over a long distance. I have to connect it. In addition, the risk of noise induction from the outside is increased due to long distance routing, and the operation may be unstable. (Ii) It is not economical because hardware and software such as a line driver and a receiver for transmitting and receiving each terminal status signal between each control circuit are required. (iii) Since most of the information processing is performed by software, the control program becomes complicated and not economical. (Iv) Since the hardware and software configurations of the first to (n-1) th co-located terminals are different from those of the n-th co-located terminal (that is, only the n-th co-located terminal requires a busy detection circuit and its processing program), the device construction Becomes complicated. An object of the present invention is to solve the above problems (i) to (iv) and the like, and to provide a no-ringing terminal multi-connection circuit that enables autonomous control.

[0007]

Means for Solving the Problems] To solve the above problems
In addition, the invention of claim 1 of the present invention is connected to an exchange.
Communication line and main terminal with outgoing and incoming functions
And the communication line and the main
Multiple co-located terminals connected to the terminal by communication lines
To the no-ringing terminal multi-connection circuit.
And each of the juxtaposed terminals and the control circuit as follows:
Make up. That is, each of the attached terminals is connected to the communication line.
And the main terminal are cascaded by the communication line.
Detected that the main terminal is sending or receiving
-Hook detection means for outputting an off-hook detection signal
A communication line on the exchange side and a communication line on the main terminal side
And the communication line on the main terminal side is exchanged.
Communication line on the machine side or the off-hook detection means
First switching means for connecting to the switch, and communication on the exchange side;
Provided between the line and the communication line on the main terminal side,
A main terminal and any one of the plurality of co-located terminals
Is busy or outgoing
Signal and a busy detection circuit that outputs a signal
Between the connection points with the busy detection circuit.
Or a second switching means for short-circuiting between the connection points.
The operation of the busy detection circuit is prohibited by short-circuiting
And open the connection points, thereby
Said second switching means for permitting operation of the output circuit;
A control circuit for controlling the first and second switching means.
I have. Further, the control circuit is configured to control the plurality of co-located terminals.
If the terminal is outgoing,
The communication line on the main terminal is connected to the communication line on the exchange
The first switching means is controlled so that
Opening the connection between the output circuit and the second switching means
Controlling the second switching means as described above, and in this state,
When the detection signal is not received, the communication of the main terminal side is performed.
Before the transmission line is connected to the off-hook detection means
And controlling the first switching means so that the busy detection circuit is connected to the second switching means.
The second connection means is short-circuited between the connection points with the second switching means.
By controlling the switching means, the outgoing call of the attached terminal is performed.
If the busy detection signal is received,
It is configured to cancel outgoing calls. The invention of claim 2
The control circuit according to claim 1, further comprising:
When a signal is received, the communication line on the main terminal side
The first switching means so as to be connected to a communication line on the machine side.
Outgoing and incoming calls of the main terminal
It has a configuration to make it look good. The invention of claim 3 is equivalent to claim 1
Or the second switching means is short-circuited between the connection points.
Between the connection points by the second switching means when
It is composed of elements with small voltage drop.

[0008]

According to the present invention, since the configuration of the non-ringing terminal multi-connection circuit as described above, the off-hook detecting means in each hotel terminal, the main terminal or the hotel's in use,
Its tail to detect the off-hook state of the bottom terminal of the subsequent terminal
A hook detection signal is provided to the control circuit. The control circuit of each of the co-located terminals controls the switching of the first and second switching means . When the first switching means is operated, the lower terminal after the hotel terminal in use is disconnected from the communication line. When the second switching means is operated during the time and communication standby, between the connection point between the busy detection circuit is opened. Thus, a so-called autonomous control in which the terminals transmit and receive asynchronously by the control circuit in each terminal can be performed.

[0009]

FIG. 1 is a circuit diagram of a non-ringing terminal multi-connection circuit showing an embodiment of the present invention. Elements common to those in FIG. 2 are denoted by common reference numerals. The non-ringing terminal multi-connection circuit comprises a main terminal 10 such as a telephone as well as FIG. 2, and a first to n-site terminal 20A ₁ through 20a _n different same circuit configuration as in FIG. 2, these
Is connected to the communication lines 1 and 2 via the communication line
Has become . Each hotel terminal 20A ₁ through 20a _n are similar polarity inversion detection circuit 23 ₁ ~ 23 _n, a bell signal detection circuit 24 ₁ ~24 _n, DP / PB transmitting circuit 25 ₁ to 25 _n, the current loop forming circuit and Fig. 2 26 _{1 to} 26 _n , transformers 27 _{1 to} 27 _n ,
Hybrid circuits 28 _{1 to} 28 _n , modems 29 ₁ to 2
9 _n, and has a meter sensor 30 ₁ to 30 _n, respectively, in each of these modems 29 ₁ ~ 29 _n and the meter sensor 30 ₁ to 30 _n, the control circuit having a configuration different from that of FIG 31
A ₁ ~31A _n are respectively connected, further off-hook detection circuit to their respective control circuits 31A ₁ ~31A _n
(Off-hook detecting means) 32 _{1 to} 32 _n are connected respectively. In addition, each hotel terminal 20A in ₁ through 20a _n,
Each control circuit 31A ₁ ~31A _n first switch which is switched controlled by (first switching means) 33 ₁ ~ 33 _n and a second switch (second switching means) 34 ₁ ~34 _n, the communication line and busy detection circuit 40A ₁ ~40A _n for outputting a row I detection information monitoring (busy detection signal) of the state are provided. Each first switch 33 ₁ ~ 33 _n are two switch contacts 33 _1a, 3
3 _1b ~33 _na, 33 have _nb, one switching contact 33 _1a ~
33 _na is one input terminal of each hotel terminal 20A ₁ ~20A _n 21 ₁ ~21 _n or each hook detection circuit 32 ₁ to 32 _n
Of can select the input side, and the other switching contact 33 _1b ~ 33 _nb and the other input terminals 22 ₁ to the hotel's terminal 20A ₁ through 20a _n
22n or earth can be selected. Each of the second switches 34 _{1 to} 34 _n is connected to each of the busy detection circuits 40A ₁ to 40A.
Input of 40A _n, and a switching contact 34 _1a to 34C _na for short-circuiting between the output terminals (between connection points). Each busy detection circuit 40A ₁ ~40A _n, in order to determine the amount of free or busy communication lines 1, 2 at the start of the hotel terminal originating, switching contact 34 _1a to 34C _na second switch 34 ₁ to 34C _n Is temporarily inserted to enter the insertion state, and has a function of monitoring the line state (communication lines 1 and 2). ₁ Each busy detection circuit 40A ~40A _n, each hotel terminal 20A ₁ to 20
One input to the terminal 22 ₁ through 22 _n of the A _n, the first switch 33 ₁
Between ~ 33 _n switching contact 33 _1b ~ 33 _nb of are connected. One switching contact 3 of the first switching device 33 _n
3 _na is connected to one input terminal of the main terminal 10 such as a telephone, the other input terminal of the main terminal 10 is connected to the other switching contact 33 _nb of the first switch 33 _n. First switch 33 ₁ of the switching contacts 33 _1a, 33 _1b of the first features terminal 20A ₁ is connected to an input terminal 21 _2, 22 ₂ of the second-site terminal 20A _2, the second features terminal 20A in ₂ first switch 33 _{and second} switch contact 33 _2a, 33 _2b is connected to the input terminal of the third hotel terminal 20A _3, hereinafter similarly switching contact 33 _na of the first switch 33 _n at the n-site terminal 20A within _n , 33 _nb . Each terminal 2
Off-hook detection circuit 0A within _{1 ~20A n} 32 _{1 ~32
n} detects the off-hook condition of the main terminal 10 or the lower terminal, a circuit for supplying the detected information (off-hook detection signal) to the control circuit 31A ₁ ~31A _n. Each control circuit 3
1A ₁ ~31A _n is the main terminal 10 or features terminal 20A ₁
Receive busy information and calling information detected in through 20a _n, each hook detection circuit 32 ₁ to 32 _n each first switch based on the output or the like of 33 ₁ ~ 33 _n and the second switch 34 _1-3
4 _n , and has a function of switching control of the polarity inversion detection circuits 23 ₁ to 23 _n , a bell signal detection circuit 24 _{1 to} 24 _n ,
And a function of controlling the internal terminal in accordance with each output information of the off-hook detection circuits 32 _{1 to} 32 _n . FIG.
Is a circuit diagram showing a configuration example of a busy detection circuit 40A ₁ ~40A _n shown in FIG. Each busy detection circuit 40A _{1 in} FIG.
～40A _n is composed of, for example, each photocoupler 41. The photocoupler 41 includes a light emitting diode (hereinafter, referred to as an LED) 41a on the input side and a phototransistor 41b on the output side. LED4
1a, each hotel terminal 20A ₁ through 20a _n one input terminal 22 ₁ through 22 _n and the first switch of 33 ₁ ~ 33 _n switching contact 3
3 _1b ~ 33 is connected between the _nb. Photo coupler 4
1 means that the emitter is ground and the collector is
2 are connected to the power supply potential Vcc.
The collector of the phototransistor 41b is connected to each control circuit 3
It is connected to 1A ₁ ~31A _n. In LED41a,
In parallel with this, the switching contacts 34 of each of the second switching devices 34 _{1 to} 34 _{n
1a ~34 na} is connected. This second switch 34 _1-
34 _n is composed of a voltage drop is small semiconductor element and the output portion such as a relay or a bi-directional optical MOS relay or the like (contact portion).

[0010] Next, transmission operation of the main terminal 10 of the telephone set (1), the reception operation of the hotel's terminal 20A ₁ through 20a _n (2),
Interrupt operation of the main terminal 10 at the hotel terminal receiver (3), features terminal 20A ₁ through 20a _n transmission operation of (4),
The interruption operation (5) of the main terminal 10 at the time of transmission from the attached terminal will be described. (1) Operation when the main terminal 10 makes a call When the main terminal 10 such as a telephone makes a call, the loop current from the communication line 1 is turned off by hooking the main terminal 10 off, so that the communication line 1 → the input terminal 21 ₁ → Switching contact 33 _1a →
Input terminal 21 ₂ → Switching contact 33 _2a → ... → Input terminal 21 _n →
Switching contact 33 _na → main terminal 10 → switching contact 33 _nb → switching contact 34 _na → input terminal 22 _n → ... → switching contact 33 _2b → switching contact 34 _2a → input terminal 22 ₂ → switching contact 331 _1b → switching contact 34 _1a. → Input terminal 22 ₁ → Communication line 2 allows communication. The main terminal 10 in the state of on-hook, the first to n-th features terminal 20A ₁ through 20a _n,
The switch connected to the communication lines 1 and 2 is in a state where both reception and transmission are possible. (2) when the operation-site terminal 20A ₁ through 20a _n when hotel terminal 20A ₁ through 20a _n is listening is listening by the activation signal from the exchange, by receiving the polarity inversion signal from the switch, the 1 to n-th terminal 20A _{1 to} 20
The polarity inversion detection circuit 23 ₁ ~ 23 _n are operated in A _n, to form a small current loop. Then, the specific information of the co-located terminal that performs communication is transmitted from the exchange, and the specific information is
Transformers 27 ₁ to 2 in _n-th terminal 20A _{1 to} 20An
7 _n → hybrid circuit 28 _{1 to} 28 _n → modem 29 ₁ to 2
Received via the 9 _n, it is transmitted to the control circuit 31A ₁ ~31A _n. For example, operates as follows in the case identifying information of the hotel's terminal is a second-site terminal 20A _2. That is, the received information is transmitted to the control circuit 31A2 in the _second co-located terminal 20A ₂ and the unspecified first co-located terminal 2A 2
0A ₁ and third to n-site terminal 20A ₃ through 20a _n, together with the specific information in the control circuits 31A ₁ and 31A ₃ ~31A _n of them are reset is determined not to be the terminal itself, the specific second the hotel's terminal 20A ₂ are, together with the control circuit 31A first drives the switching device 33 ₂ by _2, switches the one switching contact 33 _2a from the input terminal 21 ₂ side to the hook detection circuit 32 ₂ side, and the other Switching contact 3
_32b is switched from the switching contact _342a side to the ground side. At the same time, second-site terminal 20A by the control circuit 31A ₂ in the ₂ drives the current loop forming circuit 26 _2, communicate current required to the communication line 1 → the input terminal 21 ₁ → switching contact 33 _1a
→ Input terminal 21 ₂ → Current loop forming circuit 26 ₂ → Input terminal 22 ₂ → Switching contact _331b → Switching contact 34 _1a → Input terminal 22 ₁ → Communication state is set by flowing to communication line 2, Communication takes place.

(3) The main terminal 1 at the time of receiving the attached terminal
Interrupt operation of 0 When the main terminal 10 goes off-hook during the communication of the above (2), the off-hook current causes the off-hook detection circuit 32 ₂ → switching contact 33 _2a →... → switching contact 33 _na → in the second auxiliary terminal 20A ₂ → Main terminal 10 → switching contact 33 _nb → switching contact 34 _na
→ Input terminal 22 _n →... → Switching contact _332b → Flow to ground. Therefore, off-hook detecting circuit 32 ₂ of the second-site terminal 20A in ₂ operates, the output signal is the control circuit 31
It is transmitted to A _2, to interrupt the second features terminal 20A ₂ in communication, thereby aborted forcibly communication through the control circuit 31A _2. Furthermore, to reset the first switching device 33 _2,
The main terminal 10 can be used by connecting those switching contacts 33 _2a and 33 _2b to the second joint terminal input terminals 21 ₂ and 22 ₂ , respectively. (4) When the hotel's terminal 20A ₁ through 20a _n becomes the operation control circuit 31A ₁ ~31A _n is programmed in, or time to send the preset data in each hotel terminal when performing an outgoing And each meter / sensor 30 ₁ to 30 _n
A description will be given of a case where the additional terminal (for example, the second additional terminal 20A ₂ ) makes a call when it becomes necessary to transmit the alarm information from.

[0012] First, the control circuit 31A ₂ of the second-site terminal 20A in _2, to operate the second switch 34 _2, by temporarily opening the switching contact 34 _2a, the use of the communication line 2 Perform a status check (that is, a busy check). That is, the LEDs 41a of the busy detection circuit 40A2 shown in FIG. 3 are temporarily inserted into the communication lines 1 and ₂ . For example, the lower terminal (i.e., third to n-site terminal 20A ₃ through 20a _n and the main terminal 10) when is in use, because the communication circuit 1 and 2 are flow loop current,
A current flows through the LED 41a. Therefore, its phototransistor 41b, the communication line 1 and 2 by the detection output that is being used appears, is transmitted to the control circuit 31A _2, outgoing is suppressed. If the contrary, the lower terminal (20A ₃ ~20A _n, 10) is not in use,
Since no loop current flows in the communication circuits 1 and ₂ , the phototransistor 41b in the busy detection circuit 40A2
, A detection output indicating that the communication lines 1 and 2 are empty is obtained. The control circuit 31A ₂ that received this detection output,
First switch 33 ₂ drives, the switching contact 33 _2a, 33
By switching _2b from second features terminal input terminals 21 _2, 22 ₂ side, respectively to the hook detection circuit ₃₂₂ side and the ground side, the communication line 1 the third to n-site terminal 20A ₃ through 20a _n and the main terminal 10 , 2. Then, the signal from the DP / PB transmitting circuit 25 of the _second-site terminal 20A _2, calls the connected switching system to the communication line 1, the current loop after the call completes, the communication line 1 → the input terminal 21 ₁ → switching contact _331a → second joint terminal input terminal 21 ₂ → DP / PB sending circuit 25 ₂ → second joint terminal input terminal 22 ₂ → switching contact _331b → switching contact 34 _1a → input terminal 22 ₁ → communication line 2 and the second co-located terminal 20A
The _second data meter sensor 30 ₂ → modem 29 ₂ → hybrid circuit 28 ₂ → communication line through the transformer 27 ₂ 2
→ Send to the exchange for communication. On the other hand, when the first hotel terminal 20A ₁ is a top terminal is in use, the first hotel terminal 20A ₁ in the switching contact 33 _1a, 33 _1b is switched respectively to the hook detection circuit 32 ₁ side and the ground side thereof Therefore, the same operation as the interruption operation of the main terminal 10 at the time of receiving the attached terminal in the above (3) is performed. That is, the first co-located terminal 2 has the same sequence as described in (2) above.
If 0A ₁ was in communication, the second features terminal 20A ₂ tries move on transmission operation. Therefore, the off-hook detection current is supplied to the off-hook detection circuit 3 in the _{first additional} terminal 20A1.
2 ₁ → Switching contact 33 _1a → Second terminal input terminal 21 ₂ → D
P / PB transmission circuit 25 ₂ → second joint terminal input terminal 22 ₂
→ Switching contact _331b → Flow to ground. 1st terminal 2
Hook detection circuit 32 ₁ 0A ₁ detects the off-hook detection current, to provide the detection information to the control circuit 31A _1, the first hotel terminal 20A ₁ communication during the communication is aborted forcibly. At the same time, the first switch 33 ₁ of the first features terminal 20A ₁ switches the switching contact 33 _1a, 33 _1b to the communication line 1 side. 2nd terminal 20A
₂ switches each of the first switch 33 _{and second} switch contact 33 _2a, 33 _2b to hook detection circuit 32 ₂ side and the ground side. As a result, transmission is possible. In this case, a function to prioritize transmission from the lower terminal is provided. (5) Interruption operation of main terminal 10 at the time of transmission of the attached terminal When the main terminal 10 goes off-hook during the communication of the above (4), the off-hook current becomes the off-hook detection circuit 32 ₂ in the second attached terminal → switching contact _{332 a} →. → input terminal 21 _n → switching contact 33 _na → main terminal 10 → switching contact 33 _nb → switching contact 34
_na → input terminal 22 _n →... → switching contact _332b → ground. Therefore, off-hook detecting circuit 32 ₂ of the second-site terminal 20A in ₂ operates, the output signal is the control circuit 3
The signal is transmitted to 1A ₂ and interrupts the _{second connected} terminal 20A ₂ during communication, thereby forcibly terminating the communication through the control circuit 31A ₂ . Furthermore, to reset the first switching device 33 _2,
The switching contacts 33 _2a and 33 _2b are connected to the input terminal 2 respectively.
By connecting to one _2, 22 ₂ side, the main terminal 10 becomes available.

As described above, this embodiment has the following advantages. (I) for each hotel terminal 20A ₁ through 20a _n, first switch 33 ₁ ~ 33 _n of circuits connected to the terminals located in the lower part
At least one position, the second switch 34 ₁ to 34C _n busy detection circuit 40A in parallel with the switching contact 34 _1a to 34C _na of between up to the switching contact _{33 1a, 33 1b ~33 na,} 33 nb ₁
Since Ａ40 _An is connected, so-called autonomous control in which each terminal transmits and receives asynchronously can be performed. (Ii) Since the autonomous control of (i) can be performed,
And the like. Hardware and software associated with it a driver and a receiver like a bus line for connecting the control circuits 31A ₁ ~31A _n becomes unnecessary. It is possible to simplify the information program in the control circuit 31A ₁ ~31A _n. All hotel's terminal 20A ₁ through 20a _n can be configured in the same hardware and software, equipment construction is simplified. (Iii) the busy detection circuit 40A ₁ ~40A _n, the second switch 34 during the time and communication standby ₁ to 34C _n switching contact 3
Since it was short-circuited by 4 _1a to 34C _na, there is no subtracting the operation voltage of the terminal, and the current margin to the communication line 2. Note that the present invention is not limited to the above-described embodiment. For example, each of the co-located terminals 20A _{1 to} 20A _{n in} FIG.
Can be transformed into another circuit configuration, or each busy detection circuit 4 in FIG.
Etc. constituting 0A ₁ ~40A _n in circuits other than the photo-coupler 41, and various modifications are possible.

[0014]

As described in detail above, claims 1 and 2
According to the invention of beauty 2, for each hotel terminal, a second switching means
Since the busy detection circuits whose operations are controlled by the respective devices are provided, so-called autonomous control in which each terminal transmits and receives asynchronously can be performed. By enabling this autonomous control, hard c E A and software associated therewith is not required of drivers and receivers like a bus line for connecting the respective control circuits. Furthermore, on which can simplify the processing program in the control circuit, since all features terminal can be configured in the same hard c E A and software, there is an effect such that equipment construction is simplified. Claim 3
According to the invention, the second switching means, so <br/> voltage drop across the connection point is constituted by not a small element, the second switching
The means short-circuits the busy detection circuit during standby and during communication, and does not reduce the operating voltage and current margin of the terminal with respect to the communication line at all.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a non-ringing terminal multiple connection circuit showing an embodiment of the present invention.

FIG. 2 is a circuit diagram of a conventional no-ringing terminal multi-connection circuit.

FIG. 3 is a circuit diagram showing a configuration example of a busy detection circuit in FIG. 1;

[Explanation of symbols]

1,2 main terminal 20A ₁ such as a communication line 10 phone through 20a _n features terminal _{21 1, 22 1 ~21 n,} 22 n input terminals 23 ₁ ~ 23 _n polarity inversion detection circuit 24 ₁ to 24 _n bell signal detection circuit 25 _{1 ~25 n} DP / PB transmitting circuit 26 ₁ ~ 26 _n current loop forming circuit 27 ₁ ~ 27 _n transformer 28 ₁ ~ 28 _n hybrid circuit 29 ₁ ~ 29 _n modem 30 ₁ to 30 _n meter sensors 31A ₁ ~31A _n the control circuit 32 ₁ to 32 _n hook detection circuit 33 ₁ ~ 33 _n first switch _{33 1a, 33 1b ~33 na,} 33 nb switching contact 34 ₁ to 34C _n second switch 34 _1a, 34 _na switching contact 40A ₁ -40A _n Busy detection circuit 41 Photocoupler

Claims (3)

(57) [Claims] 1. A communication line connected to an exchange, A main terminal having a calling function and a receiving function, The communication line and the main terminal having a calling function and a receiving function
And multiple co-located terminals connected by communication lines between
In the no ringing terminal multi-connection circuit having Each of the attached terminals, A communication line is provided between the communication line and the main terminal.
Connected in cascade, Detecting that the main terminal is making or receiving a call
Off-hook detection means for outputting an off-hook detection signal, The communication line on the exchange side and the communication line on the main terminal side
The communication line on the main terminal side is provided between
Either the communication line or the off-hook detecting means
First switching means connected to the The communication line on the exchange side and the communication line on the main terminal side
Any of the above terminals is placed outgoing or incoming
Busy detection that detects busy and outputs a busy detection signal
Output circuit, The busy detection circuit is connected in parallel to the busy detection circuit;
Switching means for opening or short-circuiting between connection points with
The short circuit between the connection points
The operation of the middle detection circuit is prohibited, and the connection point is opened.
Allowing the operation of the busy detection circuit by
Second switching means; A control circuit for controlling the first and second switching means.
And The control circuit includes: When the attached terminal makes a call, the main terminal
Before the communication line is connected to the communication line on the exchange side,
And controlling the first switching means so that the busy detection circuit is connected to the second switching means.
The second switching means so as to open between the connection points with the switching means.
Control the switching means, If the busy detection signal is not received in this state,
The communication line on the main terminal side is the off-hook detecting means
Controlling the first switching means to be connected to the
Short circuit between the connection points between the busy detection circuit and the second switching means
Let the said 2 by controlling the switching means 2
Cause the attached terminal to make a call, If the busy detection signal is received, the
No-ringing terminal machine characterized by terminating communication
Multi connection circuit. 2. The control circuit according to claim 1, wherein
When receiving the hook detection signal, the communication line on the main terminal side
Is connected to the communication line on the exchange side.
By controlling the switching means, the transmission and reception of the main terminal
No-ringing terminal characterized in that it makes incoming calls
Multi connection circuit. 3. The method according to claim 2, wherein the second switching unit connects the connection points.
The connection is established by the second switching means when the connection is short-circuited.
It must be composed of elements with small voltage drop between points.
3. The device according to claim 1, wherein
-Ringing terminal multi connection circuit.