JPS58106944A - Public telephone set - Google Patents

Abstract

PURPOSE:To prevent the coin jamming for a full cashbox due to an erroneous operation to prevent service troubles, by clearing coin information to zero if the output of a holding circuit exists when the first off-hook operation is performed after exchange of the cashbox. CONSTITUTION:Information of the operation of a cashbox contact 9 is held in a holding circuit 8 when the cashbox is pulled out, and a controlling circuit 7 monitors the output of the holding circuit 8 at the off-hook time; and if this output exists, coin information stored in a memory 73 is cleared to zero. Thereafter, a reset signal is transmitted from an output terminal 71b to reset a flip flop 83.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a public telephone set that prevents coins from being jammed due to the safe being full.゛Previously, a public phone has been proposed that accumulates information on the coins stored in the safe and stores it in memory, and when the accumulated value reaches a predetermined value of 900 million, prevents future paid calls from being made to prevent coin jams due to the safe being full. has been done.

Therefore, in the above-mentioned nine public telephones, when the safe is replaced, it is necessary to clear the accumulated coin information to zero. On the other hand, station! , 0! Kfb-1 system public telephones require the switchboard to work overtime when on-hook.
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The current that can be supplied by K4A is mlf to back up the memory.
Since only an extremely small amount of
For example, the central processing unit could only operate when off-hook.

However, in the above-mentioned public telephone, when the safe is exchanged when the control circuit is not operating and the telephone is on-hook, there is an inconvenience that the coin information stored in the memory is not cleared to zero. For this reason, the next time you go off-hook and start a call, the coin information will continue to be accumulated, and when the accumulated value reaches a predetermined value, it will be determined that the safe is full, even though the safe is not actually full. However, it had the disadvantage that subsequent paid calls would be prohibited.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a public telephone that can reliably clear the coin information stored in the memory to zero when using a safe.

In order to achieve such an objective, the public telephone of the present invention has the following features:
A holding circuit holds that the safe contact has operated when the safe is removed, and when the first off-hook operation is performed after replacing the safe, if there is a holding circuit output, the coin information is cleared to zero. . The present invention will be described in detail below using drawings showing embodiments.

The figure is a block diagram showing an embodiment of a public telephone according to the present invention. In the figure, a billing signal receiving circuit 1, a diode bridge 2, a dial impulse sending and forced disconnection circuit 3, a power supply circuit 4, a dial shut circuit 5, a telephone call circuit 6, a control circuit T, a hook switch H8, and a central office line terminal L.
IL constitutes a public telephone circuit. In addition, 8 is a holding circuit, 9 is a safe contact, and the holding circuit 8 holds 9 things when the safe contact 9 operates. Furthermore, the power supply circuit 4Fi, high resistance 41, diode 4
2 to 4B, capacitors 47 to 50, and Zener diode 51, and high resistance 41 during on-hook.
Only capacitor 50 is trickle charged through the capacitor 50, and capacitors 47 to 50 are charged by the talking current during off-hook.

The safe contact 9 is turned on when the safe is pulled out, and the holding circuit 8 that maintains that the safe contact 9 is activated includes a pull-up resistor 81, a chattering prevention circuit 82, a flip-flop 83, It is made up of resistors 84 and 85.

The control circuit T is composed of a central processing unit [(hereinafter referred to as CPU) T1, a read only memory (hereinafter referred to as ROM) 72, and a random access memory (hereinafter referred to as RAM) 73, and is written in R2M17. The CPU 71 performs necessary control according to the program, and coin information generated in a coin storage circuit (not shown) is stored in the RAM 73.

Note that the power supply voltage for the holding circuit 8 and the RAM 73 is supplied by the capacitor 50 regardless of whether it is on-hook or off-hook. The power supply voltage of the ROM 72 is supplied only when off-hook.

Further, the ROM 77 has a program written therein for the control operation to be performed by the CPU 71 after off-hook, but the first operation after off-hook is to monitor the output of the holding circuit 8, and when the output is displayed, it is stored in the RAM 73. It is a program that performs control to clear currency information to zero.

The operation of the public telephone #3 configured in this way is as follows. When the safe is replaced while on-hook to retrieve the coins stored in the safe, the safe contact 9 operates;
This 1it information is supplied to the holding circuit 8. The holding circuit 8 is on-hook as described above.

Since the power supply voltage is supplied regardless of off-hook, the flip-flop 83 connected to the safe contact 8 via the chattering prevention circuit 82 always retains this information when the safe contact T operates. The signal is then supplied to the input terminal 71a of the CPU 71 via the resistor 85. - After that, when an off-hook operation is performed, the CPU 71
The state of the input terminal 71a is monitored according to the program written in the OM72, but when the safe contact operates during on-hook, the holding output of the holding circuit 8 is supplied to this input terminal 71a, so this CPU7 depending on the situation
1iThe coin information stored in the RAM 73 is cleared to zero, and a reset signal is sent from the output terminal 71b to reset the flip-flop 83.

In this way, the operation of the safe contact 9 is on-hook.

Since it is held by the holding circuit 8 regardless of whether it is off-hook or not, there is no need for any effort associated with exchanging gold, such as going off-hook, as in the past. Furthermore, even if the safe is replaced after going off-hook as is conventional practice, the coin information in the RAM 73 is cleared to zero by the first off-hook operation after the safe is replaced.

Although the above embodiments have been described with respect to public telephones using a central power supply system, the present invention can be similarly applied to public telephones using a commercial power supply system in which the control circuit, particularly the CPU, operates off-hook.

As explained above, the public telephone according to the present invention monitors the holding output output from the holding circuit when the safe is exchanged when the holding circuit is off-hook, and when there is a holding output, the coin information is cleared to zero by the control circuit. Because it is a safe, coin information can be cleared to zero simply by replacing the safe, and for this reason, calls that are prohibited from making paid calls even though the safe is not full, which may occur due to an erroneous operation when replacing the safe. It has the effect of preventing failures and is particularly suitable for use in stored program type public filling machines.

[Brief explanation of drawings]

The figure is a block diagram showing one embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Charging signal receiving circuit, 2... Diode fringe, 3... Dial impulse sending and forced disconnection circuit, 4... Power supply circuit, 5... Dial shunt circuit, 6 ... Call circuit, 7 ... Control circuit, 8 ... Holding circuit, 9 ... Safe contact. Patent applicant Tamura Electric Manufacturing Co., Ltd. Agent
Masaki Yamakawa (#11 people)

Claims (1)

[Claims] In a public telephone whose control circuit starts operating when off-hook and stores coin information stored in a safe in a memory, a safe contact that operates when the safe is removed and a holding circuit that maintains that the safe contact has operated. A public telephone set comprising: the control circuit supervising the holding circuit output when off-hook, and clearing the coin information stored in the memory when the output is present.