JPS5846901B2 - Call control method for public telephones - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides that when a specific toll-free number is called,
This invention relates to a call control system for public telephones that allows calls without requiring the insertion of coins.

In general, public telephones are enabled to make outgoing calls by inserting a coin, allowing calls to be made by dialing and by answering the called party, but certain emergency numbers such as 110 and 119 are toll-free numbers, and coins are not accepted. dialing and calling are permitted without inputting a password.

On the other hand, if the safe that stores inserted coins in response to charging signals from the exchange machine is full, it will be impossible to store more coins, and coins that should have fallen into the safe will remain on the way. When the coin storage lever that drops coins that have been inserted and are waiting into the safe is restored, if a coin that has not yet fallen is caught, the held coin will be removed even if the coin is collected by the drawer of the safe. If the safe does not fall, there is a risk of permanent damage due to blockage of the coin passage, so a safe full detection circuit operated by hook-off is used to detect whether the safe is full or not.

In addition, the inserted coins are blocked by the coin storage lever and remain in a waiting state directly above it, but if a string-hanging coin, a coin with sticky substance attached, etc. is inserted by an unauthorized user. Then, even when the coin storage lever is operated, the coins do not fall completely and remain as waiting coins, resulting in a state in which calls are allowed forever, causing unexpected damage to the installer.

Therefore, as a countermeasure for this, it is necessary to detect the presence or absence of accumulated coins at the time of hook-off, and for this purpose, an accumulated coin detection circuit is installed to detect whether or not there are coins in the standby position directly above the coin storage lever. It has also been put into operation by hooking off.

However, conventionally, when a detection force was generated in either the accumulated coin detection circuit or the safe full detection circuit during hook-off, the loop circuit was unconditionally opened and calls were blocked. Even when making a call, it becomes impossible to make a dial call, creating a drawback that prevents emergency calls.

The present invention has the purpose of fundamentally eliminating the drawbacks of the conventional technology, and includes an abnormality detection circuit that detects the presence or absence of an abnormality in the coin passage system at the time of hook-off. A dial control circuit that generates the above judgment output, and a matching circuit that disables a call based on the judgment output when the dial control circuit judges that it is a toll call number and the detection power of the abnormality detection circuit, are provided. To provide an extremely rational call control method for a public telephone that allows a call regardless of the ability to detect an abnormal circuit when the circuit produces a judgment output of a toll-free number.

Hereinafter, the present invention will be explained in detail with reference to figures showing examples.

FIG. 1 is a connection diagram showing the main circuit of a public telephone, in which a filter unit FLU for detecting billing signals is provided between the line terminals Ll and L2 and the call line device.

A bridge circuit consisting of diodes D101 to D104 and a power supply circuit PS1 switch circuit CB are inserted, and terminals F1. F4 questions and F3. Since each section between F5 is designed to allow direct current to pass through, when the hook switch H83 is turned on due to hook-off, the wax inch H8a side becomes the positive terminal regardless of the polarity of the line terminals Ll and L2, and the switch circuit C
When B is on, a loop current flows to the telephone circuit device, and this loop current circulates through diode D11 and Zener diode ZD1, producing a Zener voltage in Zener diode ZD1, which causes voltage to flow through diodes D2 to D4. Capacitors C10 to C12 are charged, and this terminal voltage is used as a power source for various parts including a power source VDD of the semiconductor circuit.

In addition, in the switch circuit CB, when the hook switch HB3 is turned on, a positive voltage is applied to the resistors R38 and R through the telephone line device.
41 as a forward bias to the transistor Q11, and turns on the transistor Q11, so that the transistor Q10. Q9 is also turned on by the forward bias applied by the resistor R42, and remains on unless the connection point (2) between the resistors R38 and R41 becomes .L.. (low level).

Further, the capacitor C5 of the initial reset circuit IR is charged via the diode DIO and the resistor R26 in accordance with the generation of the Zener voltage of the Zener diode ZDI due to the circulation of the loop current, but the values of the resistor R26 and the capacitor C5 are Since the terminal voltage of capacitor C5 gradually increases according to a time constant determined by When the hold level is exceeded, it is rolled to el H11 (high level).

Therefore, n L tt during the period from the start of loop current flow due to hook-off until the output of the inverter 21N2 becomes tt H·tsu is trusted as the initial reset signal, and when the output of the inverter 21N2 becomes tt Hn , capacitor C2, resistor R
A differential pulse is generated from a differential circuit DF consisting of 19 and R20.

In addition, when the hook switch H82 is turned off due to hook-on, the charge of the capacitor C5 is transferred to the resistor R2.
Since ff H11 is applied to the input of the inverter 12N through 4 and transferred to its output power S a I,n, the output impedance of the inverter 12N and the resistor R2
5.

In addition, the return magnet RM of the coin storage part CM is a self-holding type having an operation winding P and a recovery winding S,
This operation drives a coin return closing lever (not shown), and the unaccommodated coins are returned.

Further, depending on the operation of the coin storage magnet KM, a coin storage lever (not shown in the figure) is driven, and the waiting coins are stored in the safe.

FIG. 2 is a block diagram showing the configuration of the control system, and the accumulated coin detection circuit SCD is composed of a light emitting element and a light receiving element, etc., which are provided opposite to each other via the coin standby position directly above the coin storage lever. The full detection circuit CBD is composed of a light emitting element and a light receiving element, etc., which are provided near the safe entrance and facing each other via a coin passage, and when both detect the presence of a coin, a detection force of .H91 is generated. It has become a thing.

In this example, each of the detection circuits SCD and CBD is used as an abnormality detection circuit that detects the presence or absence of an abnormality in the coin path or the coin path system of the safe.

The dial control circuit DC also includes a resistor R4 in FIG.
A dial pulse that detects the intermittent loop current is given by the terminal voltage of 3, and this is counted by a decimal counter to detect the dial number.
Count the number of digits in the dialed number using the decimal counter,
Based on these count results, it is determined whether the dialed number is a toll number or a toll-free number, and when it is a toll-free number, the judgment output FC is IT L +t, and when it is a toll-free number, the judgment output FC is ・Htt. .

The circuit for determining the dialed number is disclosed in detail in Japanese Patent Application No. 152575/1983 filed separately by the present applicant.

In addition, since the dial control circuit DC uses a keyboard with pushbutton switches as a dial, it houses a dialer that generates dial pulses in response to the operation of the pushbutton switch, and Similar to the pulse detection, a circuit for detecting the dial tone from the switchboard taken out from both ends of the resistor R43 is also housed, and when the dial tone is detected, the detection force DT is set to ・L +1, and when dialing,
The pulse output DP is NH11 depending on the dialed number.
, 11L II is repeated, ej L 91 pulses are sent out, and at the same time the output MU is set to L during the pulse sending period.
n.

In FIG. 2, since the input and output of each gate is numbered, when explaining the signal path, this number will be shown together with the change in signal level.

First, assuming that there are coins stuck or the safe is full, the hook-off detects this and dials the first digit of the toll number. considered impossible.

That is, when the hook-off is performed, the initial reset signal is generated as described above, which resets the flip-flop circuits (hereinafter referred to as FF) 1ON1 and 1ON2, while the differential pulse from the differential circuit DF causes
Accumulated coin detection circuit SCD and safe full detection circuit CBD
is in operation for a certain period of time, and one of the detection forces becomes ・H
Let it be I3.

Then, OR gate 17N7・H or 17N8muH
Gar 17N9 hole H → NAND gate 2ON1-H
=T causes the same gate 2ON1 to become ・Htt, and then when the first digit of the toll call number is dialed, the dial control circuit DC outputs the judgment output FC as ・Lj)
As a result, in order to reset FF1ON1 and convert its output Q to ・H, the NAND gate 12ON
2 also becomes -IHn, NAND gate 2ON3==L,
→NAND gate 19N2 = 彎L tap-19N13beH, free NOR gate 22N6th generation H, two 22N8,L
n turns off the switch circuit CB in FIG.
This state is maintained for a predetermined period of time, and the loop circuit is cut off until the exchange is restored, making calls impossible.

However, when a toll-free number is dialed for the above, the dial control circuit DC judges this and holds the judgment output FC as ・Htt, so FF1ON1
is not set, its output Q is 5, the NOR gate 22N8 maintains fl](tl, the switch circuit CB remains on, and each digit is dialed and the called party answers. Phone calls are allowed.

That is, in the above case, the NAND gate 2ON acts as a matching circuit, and the communication is disabled by matching the power of both parties.

Further, if a dial call is made to a toll telephone number without coins being inserted, the loop circuit is disconnected in the same manner as described above.

In other words, the accumulated coin detection circuit SCD either maintains the operating state caused by the differential pulse until the end of dialing, or operates again by a timer or the like after a certain period of time after operating by the differential pulse. In this way, the presence or absence of a waiting coin is detected, and in this case, the detection force is set to 11 depending on the absence of a coin.

Therefore, if you dial the toll call number with no coins inserted, the judgment output FC of the dial control circuit DC
becomes...L, so the NAND gate-1 is
2ON produces a coincidence output, which causes switch circuit C
Turn B off and disconnect the loop circuit.

However, when dialing a toll-free number, the judgment output FC of the dial control circuit DC is 14 Htl, so
NAND gate 2ON does not produce a match output and no break in the loop circuit occurs.

In addition, dial pulses are sent by the dial control circuit DC generating L91 pulses in response to keyboard operations, but after the loop circuit is closed by hook-off, dial tone is sent from the exchange. It is possible to send dial pulses only when the signal arrives.

In other words, in a normal state where the safe is full and there are coins waiting, the NAND AND gate N does not produce a matching output and the FF
11N is not set, FF1ON2 is also in the reset state, the OR gate 17N3.4・Ln is in the state, and if the dial tone has not arrived, the detection force DT of the dial control circuit DC becomes ・Hll. Because it is,
OR Age-17N6-H Tsutsu → AND gate 18N8・
The gate 18N8 is maintained at ・H99 by Hn, and when a dial call is made in this state, the output MU of the dial control circuit DC becomes ・L? 1, this is inverted by the inverter 3N, and the AND gate 18N2・H
ll, and by AND gate 18N9・H・U→NOR gate 22N8・H==−22N10・I, lt,
The output of NOR gate 1-22N is kept at ・Ln, and the pulse output DP of dial control circuit DC is ・Hn, ・L? +
Even if this is repeated, this is blocked by the NOR gate 22N, so the output of the NOR gate 22N is maintained at -IH9+, the switch circuit CB does not perform on/off operations, and no dial pulse is sent out.

On the other hand, when the dial tone arrives, the detection force DT changes to n L n, and OR Agate 17N5-L = Two 1
7N6-Ln-+AND gate 18N8-L-two 18
N9-L, -a-NORORage22N8-L.

Therefore, in order to turn on the NOR gate (22N8), N
OROR Age 2N10 also changes, this is NOR gate 2
A dial pulse is sent from the 2N8 to the switch circuit CB, which turns on and off.

As the dialer of the dial control circuit DC, a commercially available integrated circuit for generating dial pulses is suitable.For detection of the dial tone, a combination of a transducer and a detector that selects the dial tone, or a dial tone A counter or the like is used that pulses and counts the frequency, and generates a frequency selection output based on the count output during a certain period of time.

Each of the detection circuits SCD and CBD is also provided with the charging signal detection power of the filter unit FLU, and operates even when a charging signal arrives to detect the presence or absence of waiting coins and the state of the safe. .

In addition, it is possible to omit FF1ON1 depending on conditions, such as using NAND gate 2ON as an AND gate.
Various modifications are possible.

As is clear from the above description, according to the present invention, dialing of a toll-free number is allowed regardless of whether there are accumulated coins or whether the safe is full. Even in situations where calls are not possible, calls and calls can be made using toll-free numbers for emergency calls, etc., which is highly effective in various public telephones.

[Brief explanation of the drawing]

The figures show an embodiment of the present invention; FIG. 1 is a connection diagram showing the main circuit of a public telephone, and FIG. 2 is a block diagram of the control system. H83...Hook switch, DF...
Differential circuit, CB...Switch circuit, SCD...
...Accumulated coin detection circuit, CHD...Safe full detection circuit, DC...Dial control circuit, 2O
N...NANDAND gate circuit).

Claims (1)

[Claims] 1. An abnormality detection circuit that detects the presence or absence of an abnormality in the coin passage system at the time of hook-off, a dial control circuit that outputs a judgment output as to whether the dialed number is a toll-free call number or a toll-free number, and a toll-call number judgment output of the dial control circuit. and a coincidence circuit that disables a call based on a match between the detection output of the abnormality detection circuit and the detection output of the abnormality detection circuit. A call control method for public telephones characterized by allowing.