JPH0323032B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention provides a public telephone that uses a relay to detect polarity reversal of line voltage in response to a response from the other party, and also allows free calls in response to the operation of an emergency switch. It is related to.

[Prior art]

FIG. 1 is a circuit diagram showing a conventional example. When a coin is inserted after the off-hook operates the hook switch HS ¹ , a coin detection contact (hereinafter referred to as a detection contact) is activated.
When the CCL is turned on, a DC loop is closed by the communication circuit TKC, from the first line terminal _L1 to which the positive line of the telephone line (hereinafter referred to as line) is connected, to the second line terminal L1 to which the line's negative line is connected. A loop current is passed to line terminal _L2 , making it possible to make a dial call using a dial circuit not shown in the diagram, and an exchange connection is established by the response of the exchange in response to the dial call.

When the other party responds after the exchange connection is completed, the polarity of the DC voltage applied to the line from the exchange is reversed, and the voltage is transferred from the line terminal L 2 to the diode D ₅ via the make pole of the switch HS ² , which is turned on due to the off-hook _. −Talking circuit TKC−Diode D ₆ −Detection contact CCL−Diode D ₂ −Hook switch HS ²
-Response detection relay (hereinafter referred to as detection relay) ANS-
A current is passed through the route of the line terminal _L1 , which causes the latching type detection relay ANS to operate and hold.

Then, contacts ans ¹ and ans ² of the relay ANS operate, and the contact ans ¹ bypasses the diode D ₁ , and the contact ans ² prepares a recovery route for the detection relay ANS.

When an on-hook is made in response to the end of a call,
Since the power switches HS ¹ and HS ² have been restored and the line voltage has returned to its original state, the line terminal
L ₁ - Detection relay ANS - Hook switch HS ² - Contact ans ² - Diode D ₃ - Current flows in the opposite direction to that during operation through the route of line terminal L ₂ , which restores the detection relay ANS to the initial state. At the same time, the exchange is restored by opening the DC loop.

In addition, when making an emergency call, you can operate the non-locking emergency switch ES after off-hooking, and the detection contact during recovery can be activated without inserting a coin.
Power is applied to the latching type emergency relay CF via CCL, which maintains operation.
cf turns on, bypassing the detection contact CCL and closing the DC loop, making it possible to dial a specific number and make a call in response to a response from the other party.

Note that when on-hook is performed in response to the end of the call, the line terminal L ₁ - the hook switch HS ¹ is connected via the restored hook switch HS ¹ and the emergency switch ES.
- Emergency switch ES - Emergency relay CF - Detection contact
CCL - Contact cf - Diode D ₄ - Telephone circuit TKC -
The route of diode D ₇ - line terminal L ₂ conducts current in the opposite direction to that in operation, thereby triggering the emergency relay.
CF is restored and returns to its initial state.

However, such a conventional configuration requires latching type relays ANS and CF that are held in operation by permanent magnets or mechanisms, which are expensive and require space to accommodate, making it difficult to reduce the price of public telephones. Also, there are drawbacks that impede miniaturization.

[Summary of the invention]

The purpose of the present invention is to fundamentally eliminate such drawbacks of the conventional technology, and by improving the circuit configuration, the detection relay and the emergency relay can be used in common, and the same function as the conventional one can be achieved using only the detection relay. The present invention provides an extremely effective public telephone set.

〔Example〕

The details of the present invention will be explained below with reference to FIG. 2 showing an embodiment.

In the same figure, the node of the first diode _D1 is directly connected to the make contact ^HS1 of the switch connected to the line terminal _L1 , and the detection contact is connected between the cathode of this diode and one end of the communication circuit TKC.
CCL is connected and the make contact of the detection relay ANS is connected to the diode D ₁ and the detection contact CCL.
ans ¹ is connected in parallel and the diode
A second diode is connected between D ₁ and the detection contact CCL.
The anode of D ₂ is connected, the cathode of which is connected via the make pole at the transfer contact HS ² of the switch to one end of the magnetic launching type detection relay ANS.

In addition, the other end of the detection relay ANS is connected via the break pole side transfer contact of the emergency switch ES.
Connected to line terminal L ₁ , detection relay ANS
The transfer contact ans ² of the emergency switch ES has a break pole connected to the other end of the detection relay ANS through the make pole of the transfer contact of the emergency switch ES, and the transfer contact of the emergency switch ES.
Detection relay through break pole in HS ²
A make pole is connected to one end of the ANS, and
The main pole of contact ans ² is connected to the anode of a third diode D ₃ , the cathode of which is connected to the line terminal
_L2 , and is connected to the other end of the communication circuit TKC via the constant voltage diode _ZD1 .

Therefore, in response to coin insertion after the off-hook, the hook switch HS ¹ is turned on and the detection contact CCL is turned on, thereby closing the DC loop via the communication circuit TKC and the constant voltage diode ZD ₁ .
As shown in the figure, dial transmission becomes possible, and the Zener voltage of the constant voltage diode ZD ₁ inserted to generate Zener voltage with respect to the loop current charges the capacitor C ₁ via the discharge blocking diode D ₄ . The terminal voltage thereof is supplied as a local power source to the control unit CNT, and the control unit CNT, which includes a processor such as a microprocessor, a memory, etc., starts a control operation in response to the rise in the power supply voltage.

Then, when the other party answers after dialing, the polarity of the line voltage is reversed, and the line terminal L ₂ −
Diode D ₇ - Call circuit TKC - Constant voltage diode ZD ₁ - Diode D ₈ - Detection contact CCL - Diode D ₂ - Hook switch HS ² - Detection relay ANS -
Emergency switch ES - energizes in the direction of operation through the route of line terminal L ₁ , detecting relay ANS operates and holds it, diode D ₁ and detection contact CCL are bypassed by contact ans ¹ , and contact
Ans ² prepares a recovery route, and contact ans ³ sends information that the other party has responded to the control unit.
Give to CNT.

When ^the on ^- hook is performed in response to the end of the passage ^, as _shown in FIG ^.
- Diode D ₃ - Line terminal L ₂ The current in the restoration direction passes through the route, and the detection relay ANS is restored to its initial state, and the DC loop is opened and the exchange is restored.

In addition, during an emergency call, when the non-locking emergency switch ES is operated after the off-hook, line terminal L ₁ - hook switch HS ¹ - diode D ₁ -
Diode D ₂ - Hook switch HS ² - Detection relay ANS - Emergency switch ES - Contact ans ² - Diode D ₃ - Line terminal L 2 energizes in the direction of operation through the route of line terminal L ₂ , detection relay ANS maintains operation, and contact ans ¹ Diode D ₁ and detection contact CCL
Even if a coin is not inserted and the same contact CCL is off, the DC loop is closed and a call is possible, and depending on the contact ans ² , the recovery route is set as described above. make preparations for, and
Contact ans ³ gives information to the control unit CNT that the emergency switch ES has been operated.

In addition, in response to on-hook after the end of the call, power is supplied in the restoration direction through the same route as described above, and the detection relay ANS is restored.

However, the contact ans ² is early make type (E)
It is necessary to use a relay in which the break pole turns off after the detection relay ANS sufficiently approaches the operation holding state.

In addition, immediately after the start of the control operation based on the start of local power supply in response to the closure of the DC loop, the control unit CNT determines that the emergency switch ES has been operated if information from contact ans ³ is given, and specifies the While dialing a number is allowed free of charge, if information is given from contact ans ³ after a certain period of time has passed from the start of the control operation, it is determined that the other party has responded and controls the storage of coins, etc. There is.

In addition, diodes D ₂ and D ₃ are used as detection relays.
The diode _D5 , which is connected between the main pole and the break pole of the emergency switch ES, is used to prevent malfunction by passing current only in a specific direction to the ANS. This is to bypass the DC loop and prevent interruptions in the DC loop.

Therefore, by using only a single detection relay ANS, it is possible to detect the other party's response during a paid call and the operation of the emergency switch ES assuming a free call, and it is also possible to form a circuit according to these conditions. This makes it possible to easily reduce the cost and size of public telephones.

However, as the detection relay ANS, in addition to the one that maintains operation using a permanent magnet, it is also possible to use one that maintains operation mechanically.Depending on the conditions, diode _D5 may be omitted, or the contact
The same is true even if a break contact is used for ans ³ , and the power for the control unit CNT may be supplied separately, and the control operation may be started in response to the flow of a loop current or the operation of a switch contact.
In particular, various modifications are possible, such as the control unit CNT may be configured by a combination of various logic circuits without using a processor.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, two latching type relays are integrated into one, reducing the number of parts and the accommodation space, and
The price and size of public telephones can be reduced, and remarkable effects can be obtained in charge-type public telephones.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a conventional example, and FIG. 2 is a circuit diagram showing an embodiment of the present invention. L ₁ , L ₂ ... Line terminal, HS ¹ ... Hook switch (make contact), HS ² ... Hook switch (transfer contact), D ₁ to _{D 3} ... Diode, CCL ...
Detection contact (coin detection contact), TKC...Telephone circuit,
ANS...detection relay (response detection relay), ans ¹ ...
...Contact (make contact), ans ² ...Contact (transfer contact), ans ³ ...Contact, CNT...Control unit.

Claims (1)

[Scope of Claims] 1. A make contact of a hook switch connected to a first line terminal to which a positive line of a telephone line is connected; a first diode to which the make contact hair node is connected; and the first diode. a coin detection contact connected between the cathode of the coin detection contact and one end of the communication circuit; a second diode having an anode connected to a connection point between the coin detection contact and the first diode; a latching type response detection relay, one end of which is connected via the make pole of the cathode and the transfer contact of the switch; and an emergency switch, the other end of which is connected between the other end of the response detection relay and the first line terminal. A break pole is connected to the other end of the response detection relay through a break pole side transfer contact and a make pole of the transfer contact of the emergency switch, and the break pole is connected to the other end of the response detection relay through the break pole side transfer contact of the emergency switch, and A transfer contact of the response detection relay has a make pole connected to one end of the response detection relay, an anode is connected to the main pole of the transfer contact of the response detection relay, and a negative pole line of the telephone line is connected. a third diode having a cathode connected to the second line terminal and the other end of the communication circuit; and a make contact of the response detection relay connected in parallel to the series circuit of the first diode and the coin detection contact. and starts a control operation by forming a DC loop, and when detecting operation of the response detection relay immediately after the start of the control operation, determines that the emergency switch has been operated;
1. A public telephone set, comprising: a control section that determines that the other party has responded when the operation of the response detection relay is detected after a predetermined period of time has elapsed from the start of the control operation.