JPH0224298Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a telephone that can charge the internal power supply of the telephone even when the circuit board constituting the telephone circuit is removed for maintenance or the like.

Generally, public telephones powered by central office power supply use the central power supply only when off-hook to obtain operating power. If such a central power supply type public telephone is equipped with a volatile memory and an attempt is made to store, for example, counter information to prevent coins from getting jammed when the safe is full, the volatile memory In order to obtain a backup power source for the memory, it is necessary to trickle charge the backup power source with a small amount of current that does not cause the central office exchange to operate even during on-hook.

On the other hand, in response to the increasing complexity of circuits in modern telephones, the circuit board is divided into multiple parts in consideration of maintainability, versatility, and manufacturing workability, and these units are mounted inside public telephones. Things are becoming more and more common. Therefore, regardless of whether the public telephone is on-hook or not, if the board is removed during maintenance, the circuit of the removed board will contain a part of the charging path for charging the backup power supply. If this happens, the internal power supply of the public telephone cannot be charged after the board is removed, and counter information held in the volatile memory will be lost if the backup power supply is discharged.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a telephone that allows the telephone's internal power supply to continue to be charged without any hindrance when the board containing the charging path is removed.

In order to achieve this purpose, the telephone of the present invention is provided with a switch that is turned on when the board constituting the charging path is removed, and this switch is configured to be connected in parallel with the charging path of the board. It is something. The present invention will be described in detail below with reference to drawings showing embodiments.

FIG. 1 is a block diagram showing an embodiment of the telephone according to the present invention, showing the main parts of the public telephone circuit. In the figure, the public telephone circuit includes a power supply circuit 1, a charging signal receiving circuit 2, a diode bridge 3, a dial impulse sending and forced disconnection circuit 4, a telephone call circuit 5, a dial shunt circuit 6, a control circuit 7, and a current limiting circuit. 8, and a hook switch contact HS. this house,
The billing signal receiving circuit 2 and the telephone call circuit 5, which are surrounded by a dashed line, are mounted on separate boards independent of the main board on which the control circuit 7 and other call circuit parts are mounted, and these individual boards will be described later. It is electrically connected to the main board by a connector. 1
6 ₁ , 16 ₂ and 17 are switches which operate when these individual boards are removed from the connector to short-circuit and bypass disconnected portions of the charging paths mounted on the individual boards.

In addition, the billing signal in this telephone is, for example,
16KHz high frequency billing is assumed. Then, the billing signal detection section detects the voltage between the line terminals L ₁ and L ₂ and performs billing processing, but if this continues, the 16KHz billing signal will be heard by the subscriber. Although it is difficult to hear such high frequencies, it is not inaudible, and if this signal is mixed in during a phone call, it will be extremely harsh to the ears. For this reason, stop filters are inserted in series in the lines of the line terminals L ₁ and L ₂ to block charging signals. Therefore, when the charging signal receiving circuit 2 is removed, the station loop formed through its stop filter is cut off, the trickle charging loop formed during on-hook is also cut off, and the power supply for the volatile memory is cut off. You won't be able to get it. For this reason, switches 16 ₁ and 16 ₂ are provided so that when the billing signal receiving circuit 2 is removed, a disconnected station loop is formed.

Furthermore, the power supply circuit 1 includes diodes 9, 1
2, 13, capacitors 10, 14, and Zener diodes 11, 15. During on-hook, only capacitor 10 is trickle-charged by the local power supply via high resistance 8, and during off-hook, capacitors 10 and 14 carry the talking current. is charged by Voltage A of this power supply circuit 1 backs up a volatile memory (not shown) provided in the control circuit 7 regardless of whether it is on-hook or off-hook, and voltage B is supplied as an operating voltage to the control circuit 7 only during off-hook. Ru. Note that L ₁ and L ₂ are office line connection terminals.

Next, the operation of the above embodiment will be explained using an example of the connector portion shown in FIGS. 2 to 4. Figure 2~
In FIG. 4, 18 and 20 are a pair of connectors, and the main board 19 has a connector 18 and a lever 17.
A micro switch 17 with a is attached,
On the other hand, a connector 20 and a pressing plate 21 are attached integrally with the connector 20 to the individual board 51 on which the communication circuit 5 is mounted. Figure 2 shows an individual board 51.
is removed from the main board 19, and the third
The figure and FIG. 4 show a state in which the individual board 51 is inserted into the main board 19.

Therefore, the individual board 5 on which the communication circuit 5 is mounted
1 is inserted into the main board 19 as shown in FIGS. 3 and 4, the lever 17a
Since the microswitch 17 is opened as shown in FIG. 1 by being pressed by the pressing plate 21, the charging path is formed through the communication circuit 5 regardless of whether it is on-hook or off-hook. next,
When the individual board 51 on which the communication circuit 5 is mounted is removed from the main board 19 during maintenance and the state shown in FIG. If so, continue trickle charging. Therefore, there is no fear that the counter information etc. held in the memory will be lost, and coin jams are reliably prevented.

Note that the same applies when the individual board on which the billing signal receiving circuit 2 is mounted is removed, and the present invention is not limited to only these circuits.

Further, in the above embodiment, the case of a public telephone was explained, but it can of course be applied to a general telephone that retains speed dial destinations, automatic dial destinations, and other information in volatile memory even while on-hook. good.

As explained above, the phone according to the present invention automatically forms a charging path for trickle charging of the phone's internal power supply even after the board that forms the charging path is removed, so volatile memory remains intact even during maintenance. This has the advantage that the operating power supply for the device is secured, and the so-called latch-up, which is a phenomenon in which the data held therein is lost, does not occur.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention.
FIGS. 2 to 4 are explanatory diagrams showing an example of a connector portion. 1...Power supply circuit, 2...Charging signal receiving circuit, 5
...Telephone circuit, 7...Control circuit, 8...Resistance,
9, 12, 13...diode, 10, 14...
Capacitor, 11, 15... Zener diode, 16 ₁ , 16 ₂ , 17... Micro switch,
HS...Futsuku switch.

Claims (1)

[Scope of Claim for Utility Model Registration] In a telephone in which the telephone circuit is composed of a main board and an individual board, and the volatile memory power supply of the main board is charged by a local power source, the individual board that forms part of the charging path. 1. A telephone set comprising a switch that operates when the telephone is removed to short-circuit and bypass a disconnected part of a charging path mounted on an individual board.