CN1223522A - Public telephone set - Google Patents
Public telephone set Download PDFInfo
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- CN1223522A CN1223522A CN 98124434 CN98124434A CN1223522A CN 1223522 A CN1223522 A CN 1223522A CN 98124434 CN98124434 CN 98124434 CN 98124434 A CN98124434 A CN 98124434A CN 1223522 A CN1223522 A CN 1223522A
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Abstract
The invention relates a public telephone set connecting to the public telephone line, charging for the call needed to pay, to prevent free speech resulting from closing a DC loop of two lines connecting to an exchange by connecting a handset cord of a handset of a public telephone set to ground, in which a transformer connects between one terminal and the other terminal of a handset cord and each output terminal of a speech circuit to isolate the handset code from lines in terms of DC, the other terminal of the handset cord and the line are connected by a contact, and a control circuit opens the contact when the off-hook state reaches an on-hook state.
Description
The invention relates to and be connected in general telegraph circuit, carry out the public telephone set of charge for the need fee call.
The 3rd figure shows the routine in advance calcspar of public telephone set that moves by telephone power.In the 3rd figure, this public telephone set is to be connected in telephone line (being designated hereinafter simply as circuit) L1, L2 with bridge diode (DB) 1, is connected with the collection of letters testing circuit 2 of detection by circuit L1, telephone signal that L2 transmits on the outlet side of bridge diode 1.On collection of letters testing circuit 2, be connected with buzzer (BZ) 3, when collecting mail, produce ring and move.
Again, telephone line L1, L2 are connected in hangs up switch (hook switch:HS) 1, makes this junction closure by taking off microphone (off-hook), is closed into the DC loop of circuit L1, L2.Bridge diode 4 is by hanging up the voltage (L1:0V (ground connection) of switch (HS) 1 with circuit L1, the L2 of direct current closure; L2:-48V) be transformed to fixed direct voltage.And, this direct voltage supplies to power circuit 5 via the circuit force disconnect with transistor Q1, by power circuit 5 be transformed to decide voltage V, as the every power supply that is supplied to control circuit 7, dial circuit 8, display part 9, operating portion 10, coin handling part 11.
Use when so public telephone set is carried out conversation, genuine as is well known, taking off the Hou of microphone, coin is dropped into operating portion 10 Hous, the operation dial key is dialed the other side's telephone number.Right Hou, operated and the number of dialing and connecting that dial is detected by control circuit 7 and is sent to dial circuit 8, the result makes from the signal of dialing and connecting of dial circuit 8 and sends to circuit L1, L2.Notify from a phone call to the other side by this mode.This moment, the other side was if there is response, and control circuit 7 is just controlled coin handling part 11, collected the cost of the phone call of 1 charge amount among the coin of input.And in continuing conversation, 7 of control circuits are receiving each charging signal by the charging signal receiving circuit that does not illustrate, or by spontaneous charge according to each section set time Hou, just from the coin of input, collect communication cost each time, and remaining sum is when using up, then close (OFF) transistor Q1, forcibly circuit L1, L2 are cut off, conversation is ended.
Yet, one of receiver R of public telephone set end, be by hand microphone line H1, and through the capacitor C1 shown in the 3rd figure, when being connected in one of talk line 6 end, the other end then is connected in negative pole () the current potential lead-out terminal (that is, the other end of speaking circuit 6) of bridge diode 4 by another hand microphone line H2.Again, one of transmitter T end is by hand microphone line H3, and through capacitor C2, is connected in talk line 6, and the other end is then identical with receiver R, is connected in negative pole () the current potential lead-out terminal of bridge diode 4 by another hand microphone line H4.Just, the other end of receiver R and transmitter T is to be connected with the line side in the direct current mode.But because the circuit L1 among the circuit L1, the L2 that are connected with switch has earthing potential.Therefore, if with as the distribution of the other end of receiver R and transmitter T is shown in the 3rd figure ground connection when obtaining earthing potential, then as at the dotted line shown in the 3rd figure, can make the DC loop closure of circuit L1, L2, electric current I g will be from circuit L1 effluent in having-the circuit L2 side of 48V current potential.
Therefore, caused by public telephone set when the other side is notified from a phone call in dialing, hand microphone line H2, the H4 that is connected in the other end of receiver R and transmitter T given the problem that ground connection just may be carried out improper conversation.
That is, when dialing and connecting need fee-based number call the other side, hand microphone line H2, the H4 that is connected in the other end of receiver R and transmitter T given ground connection by public telephone set.Right Hou is carried out and is hung up operation, makes the public telephone pusher side that it is considered as abandoning dialing and connecting call.At this moment, for the public telephone pusher side, even transistor Q1 is closed (OFF) in certain set time Hou owing to be closed into the DC loop of circuit L1, L2 with the route shown in the 3rd figure dotted line, exchanger side then be judged as notify from a phone call or conversation continue carry out.Now is dialed and connected the service phone number of exempting from paying with public telephone set.Dial and connect number by this, quiet (mute) that the public telephone pusher side is then removed transmitter T makes phone be in the state that can converse, simultaneously because to dial and connect number be non-charge object, can't force to make line interruption and open (ON) that can keep transistor Q1.And exchanger side should free service phone number be considered as ignoring this and dialing and connecting in notifying from a phone call dialing and connecting of wiring Hou.So caused the problem of not having fee call with the other side of the initial need fee-based number of being dialed and connected.
Again, for receiving the public telephone set person who charges from charging signal that exchanger side transmitted, then shown in the 4th figure, hand microphone line H2, the H4 that makes the other end that is connected in receiver R and transmitter T during ground connection, also may cause the problem of improper conversation via capacitor C3.
That is, when dialing and connecting need fee-based number call the other side, will being connected in hand microphone line H2, the H4 of the other end of receiver R and transmitter T by public telephone set, C3 gives ground connection via capacitor.In the case, capacitor C3 is equivalent to be connected in the state between circuit L1, L2 of the 4th figure dotted line shown in partly.Under this situation, when responding, the other side notifies from a phone call and when making charge signal from exchanger side pass to circuit L1, L2, state charging signal before the 16KHz of high frequency or the 12KHz by capacitor C3, and make the charging signal receiving circuit (not illustrating) that is disposed at the Hou section can not receive this signal.And, even the charging signal that is transmitted in continuing conversation can't receive too.Thereby, may cause the problem of no fee call.
Again, shown in the 5th figure, between hand microphone line H2, the H4 and ground connection of the other end of receiver R that connects public telephone set and transmitter T, connection is with regular phone machine 100, public telephone set is remained on (on-hook) state of hanging up, dial and connect and take off phone, also may cause the problem of no fee call by this regular phone machine by the regular phone machine.
Therefore, the present invention's purpose is to prevent to utilize public telephone set to carry out as above-mentioned no fee call.
For solving the present invention of problem like this, by the following technical solutions:
A kind of public telephone set, it is to be connected in by the 1st circuit that earthing potential is arranged and more aforementioned earthing potential the 2nd telephone line that circuit became than electronegative potential arranged, has speaking circuit simultaneously, receiver-transmitter, and an end is connected in the 1st output of aforementioned speaking circuit, the other end is connected in the 2nd output of this speaking circuit, and there is direct current to be connected in the public telephone set of hand microphone line of the 2nd circuit of aforementioned telephone line, its characteristic is for having: disconnected device, it is to carry out the disconnected of direct current between the other end of aforementioned hand microphone line and aforementioned telephone line.
Described public telephone set, wherein aforementioned disconnected device are the transformers that is connected between each output of one of aforementioned hand microphone line end and the other end and aforementioned speaking circuit.
Described public telephone set, wherein aforementioned disconnected device is to have:
The switching device that is connected between the other end that makes aforementioned hand microphone line by contact and the 2nd circuit of aforementioned telephone line; And
When public telephone set becomes when hanging up state by taking off the microphone state, control makes the control device of the contact of aforementioned switches device for open circuit.
Be directed to be connected in the 2nd telephone line that circuit L2 is become than electronegative potential arranged by the 1st the circuit L1 that earthing potential is arranged and more aforementioned earthing potential, possess speaking circuit is arranged, reach receiver-transmitter simultaneously, reach the 1st output that an end is connected in speaking circuit, the other end is connected in the 2nd output of speaking circuit, and be connected in the hand microphone line of circuit L2 with direct current, public telephone set, on DC circuit, be disconnected disconnected device with being provided with between the other end of hand microphone line and the circuit.
With above-mentioned disconnected device, be the transformer of adopting with between each output that is connected in one of the hand microphone line end and the other end and speaking circuit (instrument transformer) again.
Again, with disconnected device, be by the switching device that is connected between the other end that makes the hand microphone line by contact and the circuit L2, and become when hanging up state by taking off the microphone state when public telephone set, control the contact that makes the aforementioned switches device and constituted by the control device of open circuit.
According to above illustrated the present invention, be aimed at: possess to have and be connected in circuit that 2 lines by L1 and L2 are become simultaneously, and be connected in speaking circuit, and electrophone, one end is the 1st output of speaking circuit, the other end is for being connected in the 2nd output of speaking circuit, and be connected in the public telephone set of the hand microphone line of circuit L2 with direct current, owing to adopt to be provided with between hand microphone line and the circuit and do not do the disconnected device that is connected on the DC circuit, even with hand microphone line ground connection, the hand microphone line also can make DC circuit separate with the line side, because can not form circuit L1, the DC loop of L2 is so can prevent to utilize all improper conversations such as ground connection of hand microphone line.
Again, as disconnected device, owing to be between each output with one of hand microphone line end and the other end and speaking circuit, connection is in the mode of transformer, simple by this formation, and can prevent improper conversation really.
Again, as disconnected device, utilize contact between the other end of hand microphone line and the circuit L2, be provided with the converting switch device of connection, public telephone set becomes when hanging up state by taking off the microphone state, the contact of control its switch device is open circuit, because the DC loop of circuit is an open circuit, dial and connect need fee-based number Hou by public telephone set, desire to hang up operation when carrying out no-charge call with execution, because the aforementioned DC loop of hanging up functional arrangement is open circuit, therefore can prevent to utilize to connect to dial needs fee-based number and carries out no-charge call.
Below embodiments of the present invention will be described in detail with reference to the accompanying drawings:
The 1st figure is the calcspar of the present invention's public telephone set the 1st example.
The 2nd figure is the calcspar of the 2nd example of above-mentioned public telephone set.
The 3rd figure is the 1st example of the improper conversation of public telephone set in advance.
The 4th figure is the 2nd example of the improper conversation of public telephone set in advance.
The 5th figure is the 3rd example of the improper conversation of public telephone set in advance.
Below, with reference to drawing explanation embodiments of the invention.
The 1st figure is the calcspar of the present invention's public telephone set the 1st example.On same figure, this public telephone set is to be connected in telephone line L1, L2 with bridge diode (DB) 1, is connected with collection of letters signal is transmitted in detection by telephone line L1, L2 collection of letters testing circuit 2 on the outlet side of bridge diode 1.On collection of letters testing circuit 2, be connected with buzzer (BZ) 3, when collecting mail, produce ring and move.
Again, telephone line L1, L2 are connected in hangs up switch (HS) 1, makes this junction closure by taking off microphone (off-hook), is closed into the DC loop of circuit L1, L2.Bridge diode 4 is by hanging up the voltage (L1 of switch (HS) 1 with circuit L1, the L2 of direct current closure; 0V (ground connection), L2;-48V) be transformed to fixed direct voltage.And, this direct voltage supplies to power circuit 5 via the circuit force disconnect with transistor Q1, by power circuit 5 be transformed to decide voltage V, as the every power supply that is supplied to control circuit 7, dial circuit 8, display part 9, operating portion 10, coin handling part 11, charging signal receiving circuit 12.
Yet, use when so public telephone set is carried out conversation, genuine as is well known, taking off the Hou of microphone, coin is dropped into operating portion 10 Hous, the operation dial key is dialed the other side's telephone number.Right Hou, operated and the number of dialing and connecting that dial is detected by control circuit 7 and is sent to dial circuit 8, its result makes from the signal of dialing and connecting of dial circuit 8 and sends to circuit L1, L2 side.Carry out the other side's call by this mode.This moment, the other side was if there is a response, and when the switch that never illustrates out when charging signal transmitted circuit L1, L2, this charging signal was output in control circuit 7 via transformer T3 in charging signal receiving circuit 12 received signals.Thus, control circuit 7 is just controlled coin handling part 11, the cost of the phone call of 1 charge amount of levy among the coin of input.And in continuing conversation, when charging signal arrives, just from the coin of inputs, collect communication cost each time, and the residue amount of money is then closed (OFF) transistor Q1 when using up, and forcibly circuit L1, L2 is cut off, and making the end of a period of conversing.
In this this public telephone set, the two ends of receiver R be connected in transformer (instrument transformer) via hand microphone line H1, H2 one side T1 simultaneously, the another side of transformer T1 then is connected in speaking circuit 6.Again, the two ends of transmitter T are connected in transformer (instrument transformer) T2 on one side via hand microphone line H3, H4, and the another side of transformer T2 then is connected in speaking circuit 6.
That is by with transformer T1, T2 makes it to separate on DC circuit with between each hand microphone line that two ends connected of receiver R and transmitter T and the speaking circuit 6, and makes the hand microphone line be separated on DC circuit with the line side.
So, even with the hand microphone line ground connection of this public telephone set and since hand microphone line and line side on DC circuit for separating, so can not form the DC loop of circuit L1, L2.
Therefore, can prevent to cause following improper conversation owing to the ground connection of hand microphone line.
That is, in using public telephone set, dial and connect when needing fee-based number to notify from a phone call the other side taking off phone, why pettyly again make hand microphone line ground connection, the DC loop of circuit L1, L2 also not can as the 3rd figure closure.Therefore, it takes second place and hangs up (hooking) when operation with public telephone set, and control circuit 7 detects it by hanging up switch HS2, make transistor Q1 closing (OFF) even certain hour Hou circuit broken string, this signal then is communicated to exchanger side.So, above-mentionedly need dialing and connecting of fee-based number to notify from a phone call to be abandoned ending and notify from a phone call being connected of the other side owing to then judging at exchanger side, thus can prevent to utilize above-mentioned connect to dial need fee-based number and carry out no-charge call.
Again, shown in the 4th figure, be connected capacitor 3 with the ground interpolar at the hand microphone line, by this capacitor 3, allow from the charging signal of exchanger side by the time, can be because the hand microphone line have separated the DC circuit with the line side, so charging signal is passed through.Therefore the charging signal from switch is just received by the charging signal receiving circuit, and is conveyed to control circuit, in response to carrying out collecting of coin in this.By this, can prevent that utilization from connecing group need fee-based number and carrying out no-charge call.
Again, shown in the 5th figure, be connected regular phone machine 100 at the hand microphone line with the ground interpolar, take off microphone and dial and connect and carry out improper conversation with regular phone machine 100 even want, taking off in the microphone when regular phone machine 100, because the DC loop of circuit can't be closed.Therefore can prevent to utilize regular phone machine 100 to connect to dial needs fee-based number and carries out no-charge call.
Secondly, the 2nd figure is the calcspar of the present invention's public telephone set the 2nd example, is connected with transistor Q2 or relay tip RL between negative () the current potential lead-out terminal of the hand microphone line H2, the H4 that are connected in receiver R and the other end of transmitter T and bridge diode 4.And in circuit L1, the L2 of public telephone set during in the open circuit action, that carries out transistor Q2 closes (off) or the open circuit of relay tip RL, and open a way hand microphone line H2, H4 combine with direct current between the line side.
Therefore, as shown in the 3rd figure, dial and connect when needing fee-based number to notify from a phone call the other side using telephone set to take off microphone, even with hand microphone line H2, H4 ground connection makes circuit L1, the DC loop closure of L2, right Hou is when carrying out hanging up of public telephone set when operating, folder is situated between and detects this control loop circuit of hanging up operation and make transistor Q1 cut out (off) while with certain hour by hanging up switch (HS) 2, because this moment, transistor Q2 was for closing, or relay tip RL is open circuit, thereby hand microphone line H2, direct current between H4 and the line side is combined into open circuit, circuit L1, the DC loop of L2 becomes open circuit.By this, above-mentionedly need dialing and connecting of fee-based number to notify from a phone call to be abandoned ending and notify from a phone call being connected of the other side owing to judging at exchanger side, thus can prevent to utilize above-mentioned connect to dial need fee-based number and carry out no-charge call.
Claims (3)
1. public telephone set, it is to be connected in by the 1st circuit that earthing potential is arranged and more aforementioned earthing potential the 2nd telephone line that circuit became than electronegative potential arranged, has speaking circuit simultaneously, receiver-transmitter, and an end is connected in the 1st output of aforementioned speaking circuit, the other end is connected in the 2nd output of this speaking circuit, and be connected in the public telephone set of hand microphone line of the 2nd circuit of aforementioned telephone line direct current, its characteristic is for having: disconnected device, it is to carry out the disconnected of direct current between the other end of aforementioned hand microphone line and aforementioned telephone line.
2. public telephone set according to claim 1, wherein aforementioned disconnected device are the transformers that is connected between each output of one of aforementioned hand microphone line end and the other end and aforementioned speaking circuit.
3. public telephone set according to claim 1, wherein aforementioned disconnected device is to have:
The switching device that is connected between the other end that makes aforementioned hand microphone line by contact and the 2nd circuit of aforementioned telephone line; And
When public telephone set becomes when hanging up state by taking off the microphone state, control makes the control device of the contact of aforementioned switches device for open circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 98124434 CN1223522A (en) | 1997-11-04 | 1998-11-03 | Public telephone set |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP302219/97 | 1997-11-04 | ||
| CN 98124434 CN1223522A (en) | 1997-11-04 | 1998-11-03 | Public telephone set |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1223522A true CN1223522A (en) | 1999-07-21 |
Family
ID=5228643
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 98124434 Pending CN1223522A (en) | 1997-11-04 | 1998-11-03 | Public telephone set |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1223522A (en) |
-
1998
- 1998-11-03 CN CN 98124434 patent/CN1223522A/en active Pending
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| Date | Code | Title | Description |
|---|---|---|---|
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C06 | Publication | ||
| PB01 | Publication | ||
| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |