JPS6312608Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is a public telephone connected to an exchange system in which a coin storage signal does not arrive from the exchange when a called party answers, and in particular, the public telephone can be operated by operating a special key (hereinafter referred to as KS key). This invention relates to the improvement of public telephones equipped with a switching function that allows them to be used in the same way as regular subscriber telephones without using coins.

Conventionally, this type of public telephone has been disclosed, for example, in the Japanese Utility Model Application Publication No. 1980-1989.
As described in Publication No. 51016, inserting a coin would operate a latching relay to short-circuit the transmitter, and by operating a push button switch, the coin would be inserted and the short-circuiting of the transmitter would be released, making it possible to talk (transmit).

Therefore, since such public telephones use a latching relay, the telephone itself has the drawback of becoming larger and heavier.

Furthermore, when making a call by operating the KS key or using a toll-free number, there was an inconvenience that even if a loop was formed, if a coin was inserted by mistake, the call could not be made.

In view of the above points, this invention was devised to eliminate the above-mentioned drawbacks and to solve such problems.The purpose of this invention is to reduce the size and weight of the telephone itself through electronicization, and to prevent people from accidentally using coins. Even if you put it in, KS
An object of the present invention is to provide a public telephone capable of making calls using a key as well as a toll-free number.

In order to achieve this purpose, the present invention
A transistor is connected in series with the transmitter, and this transistor is turned off by inserting a coin and then turned on by pressing a push button, or by turning on the transistor when pressing the KS key or dialing a toll-free number. Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a block diagram showing an embodiment of a public telephone according to the present invention, and shows only the parts necessary for explanation. In the figure, L ₁ and L ₂ are central line terminals, and these central line terminals are
A bell is connected to L ₁ and L ₂ via the hook switch HS.
A series circuit of BELL and capacitor _C1 is connected, and a diode bridge circuit DB is also connected. POW is the logic circuit (control circuit) and the power supply circuit of the coin storage magnet, Di is the impulse contact of the dial, SHT is the short circuit of the dial impulse contact Di, and Ds is activated by fingering the dial and is restored just before the release ends. Transceiver T while dialing,
Dial shunt contacts, KS ₁ and KS ₂ , which short-circuit the communication circuit consisting of receiver R, induction wire IND, capacitor C ₂ , balanced circuit network NET, etc., allow the public telephone to be used as a general subscription telephone without using coins. This key switch KS ₁ is connected in parallel to the contact L of the relay L (not shown) that operates when a coin is inserted, and the normally closed contact of the key switch KS ₂ is connected to the central line terminal L ₁ . It is connected between the dial impulse contact Di inserted in the system and the short circuit SHT, and the normally open contact is connected to the base of the transistor Tr ₄ , which is connected in series with the transmitter T via the diode D in the forward direction. There is.
The key switches KS ₁ and KS ₂ constitute a second means for turning on the transistor Tr ₄ regardless of whether or not a coin is inserted.

FF ₁ is a flip-flop that is set by the operation of a coin contact, which will be described later. FF ₂ is a flip-flop that is set by operating a pushbutton switch PB. The set input terminal S of this flip-flop FF ₁ is connected to a resistor R ₂ and a coin input terminal. It is grounded through the coin contact CC in series, which operates and is mechanically held and restored by applying the handset, and the connection point between the resistor _R2 and the coin contact CC is connected to the power supply V through the resistor _R1 . The output terminal Q is connected to one input terminal of the NAND gate NAND ₂ , and the output terminal Q is connected to one input terminal of the NAND gate NAND 2.
Connected to one input end of NAND ₁ . The other input terminal of this NAND gate NAND ₁ is connected via a resistor R ₄ to the movable contact of a pushbutton switch PB whose fixed contact side is connected to the power supply V, and the output terminal is connected to the set input terminal S of the flip-flop FF ₂ . The connection point between pushbutton switch PB and resistor _R4 is grounded via resistor _R3 . Further, the output of the output terminal Q of the flip-flop FF ₂ is sent out as the coin storage magnet operation control signal MOCS via the inverter INV, and is also input to the other input terminal of the NAND gate NAND ₂ , which further controls the short circuit SHT. It is configured as follows.

Tr ₁ , Tr ₂ and Tr ₃ are transistors, the emitter of transistor Tr ₁ is connected to the power supply V, the base of transistor Tr ₂ is connected via collector resistor R ₇ , and the base of transistor Tr ₁ is connected to resistor R ₅ . It is connected to the output terminal of the NAND gate NAND ₂ through the resistor R6, and to the power supply V through the resistor _R6 .
In addition, the collector of transistor Tr ₂ is connected to the dial.
The emitter is connected to the power circuit POW through the impulse contact Di, and the emitter is connected to the induction wire IND through the resistor _R8 .
The emitter of transistor Tr ₃ is connected to the power supply circuit POW through the dial impulse contact Di.
The collector is connected to the base of transistor Tr ₄ , and the base of transistor Tr ₃ is connected to the emitter of transistor Tr ₂ . Also, a transistor connected in series with the transmitter T
The collector of Tr ₄ is connected to the power supply circuit POW via a dial impulse contact Di, and the emitter is connected to the induction wire IND via a transmitter T and a resistor R ₉ in series.

And the above coin contact CC and flip-flop
FF ₁ , the NAND gate NAND ₂ , and the transistors Tr ₁ to _{Tr 3} turn off the transistor Tr ₄ connected in series with the transmitter T by inserting a coin.
NAND ₁ , flip-flop FF ₂ , inverter
INV, NAND gate NAND ₂ and transistor
Tr ₁ to _{Tr 3} turn on transistor Tr ₄ by pressing a push button, and these transistors turn off by inserting a coin and turn on by pressing a push button.
constitutes a means of

The KS switches _KS1 , _KS2 , diodes, and transistor _Tr4 constitute a second means for forcibly turning on the transistor _Tr4 when the telephone is used as a general telephone without using coins.

Next, the operation of the embodiment shown in FIG. 1 will be explained. First, when the handset is raised and a coin is inserted, relay L is activated and its relay contact l is closed to form a transmission loop. At the same time, the coin contact CC
The flip-flop _FF1 is set by the closing of NAND gate NAND2, and the two inputs of the NAND gate _NAND2 both become high level (hereinafter referred to as "H") and output a low level (hereinafter referred to as "L"). Also, coin contact
Closing CC sends out a relay operation control signal ROCS that determines the timing for starting the operation of relay L.

When the output of the NAND gate NAND ₂ becomes "L", the transistor Tr ₁ turns on, and accordingly, the transistor Tr ₂ turns on, the transistor Tr ₃ turns off, and the transistor Tr ₄ turns off, so that the transmission is not possible. The device T is disconnected from the central office line.

Thereafter, when the called party confirms through the receiver R that the called party has answered, the non-lock type push button switch PB is operated. At this time, Nand Gate
Since the other inputs of NAND ₁ are already at "H", the output of NAND gate NAND ₁ becomes "L" and flip-flop FF ₂ is set.

As a result, the Q output of flip-flop FF ₂ becomes "H" and the output of inverter INV becomes "L".
This "L" level signal is sent out as the coin storage magnet operation control signal MOCS and also enters the other input terminal of the NAND gate NAND ₂ , the output of the NAND gate NAND ₂ becomes "H", and the transistor Tr ₁ is turned off. to move to. When the transistor Tr ₁ is turned off, the transistor Tr ₂ is also turned off, which turns the transistor Tr ₃ on, and when the transistor Tr ₄ is turned on, the transmitter T is connected to the central office line and a call is possible. Become.

At this time, the Q output of the flip-flop _FF2 is also sent to the short circuit SHT of the dial impulse contact Di via the inverter INV, thereby prohibiting further sending of dial pulses to prevent unauthorized use.

On the other hand, when this public telephone is generally used as a subscription telephone, the key switch KS is operated.
As a result, the KS key KS ₁ is closed to form a transmission loop, and the KS key KS ₂ is switched for the first time to forcibly turn on the transistor Tr ₄ . Therefore, even if a coin is accidentally inserted, transistor Tr ₄
remains on and does not prevent outgoing calls.

In this way, by using electronic equipment that does not use a latching relay, it is possible to reduce the size and weight of the telephone. Additionally, KS key calls can be made regardless of whether or not coins are inserted.

FIG. 2 is a block diagram showing another embodiment of the present invention. In Fig. 2, the same numbers as in Fig. 1 indicate corresponding parts, and the DCC is a dial control circuit that detects and operates when a toll-free telephone number for police, fire department, etc. is dialed, and its output terminal is connected to the base of the transistor Tr ₄ via the diode D in the forward direction through the connection point of the normally open contact of the key switch KS ₂ shown in Fig. 2, and controls the transistor Tr ₄ by the output of the dial control circuit DCC. It is configured as follows. In addition, short circuit
The SHT has the ability to short the dial impulse contacts and includes a dial impulse detection circuit. The difference from Figure 1 is that
In addition to the operation of the KS key, the dial number up to the third digit is monitored, and if it is a toll-free number, the output of the dial control circuit DCC is used to switch the transistor Tr ₄ .
The reason is that I turned it on.

In addition, in the case of the above-mentioned free call, even if a coin is inserted and the push button switch PB is operated, it goes without saying that the coin should not be stored. In addition, by operating the KS key, you can open the DC loop with KS ₁ , open the dial short circuit SHT with KS ₂ , and
Since the transmission circuit transistor Tr ₄ is turned on, paid calls are also possible.

As explained above, according to the present invention, without using a latching relay as in the past,
Digitization allows phones to be made smaller and lighter, and KS can be used regardless of whether coins are inserted.
Since it is possible to make calls by key operation as well as free calls, the practical effect is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of a public telephone according to the present invention, and FIG. 2 is a block diagram showing another embodiment of the present invention. T...Transmitter, Tr ₁ to Tr ₄ ...Transistor,
KS ₁ , KS ₂ ...Key switch, PB...Push button switch, CC...Coin contact, FF ₁ , FF ₂ ...Flip-flop, NAND ₁ , NAND ₂ ...NAND gate, INV...Inverter, DCC...Dial control circuit.

Claims (1)

[Scope of Claim for Utility Model Registration] A coin-operated public telephone connected to an exchange system in which a coin insertion signal does not arrive from the central office exchange when the called party answers, and where the telephone is short-circuited by inserting a coin and the telephone is A public telephone equipped with a means for confirming the response of a person and storing coins by operating a push button switch and releasing the short circuit of the transmitter, and a switching means capable of being used as a general subscriber telephone by operating a special key, a first means for connecting a transistor in series with the transmitter, turning off the transistor by inserting a coin and then turning it on by operating the push button switch; and means for detecting the special key operation or toll-free dial number. and second means for turning on the transistor in response to a signal output from the public telephone.