JPS6376547A - Telephone set - Google Patents

Abstract

PURPOSE:To improve the making rate of dial pulses by allowing a charging circuit to rapidly charge a capacitor and rapidly stabilize a bias at the time of making a dial pulse sending circuit. CONSTITUTION:Since 1 dial circuit 6 receiving a signal turns on/off a transistor (TR)7 by the number of dial pulses to be sent, a TR 3 is also turned on/off synchronously with the TR 7 and dial pulses are sent. On the other hand, the dial circuit 6 sends a mute signal through a signal line 9, so that the capacitor 14 is directly charged through the charging circuit 20 during the sending of the dial pulses. When the TR 3 is made (turned on), the capacitor 14 is rapidly charged and the bias is rapidly stabilized. Consequently, the variation of DC voltage is reduced and the making rate of dial pulses is increased.

Description

[Detailed description of the invention] [Object of the invention 1 (Industrial application field) TECHNICAL FIELD This invention relates to a telephone.

(Prior Art) Conventionally, there has been known a telephone filter in which power is supplied from an exchange to a telephone call circuit via a dial pulse sending circuit. In such telephone supplies, the dial pulse sending circuit becomes make when the call is in progress, and power is constantly supplied to the calling circuit. However, when sending dial pulses, the dial pulse sending circuit repeats make and break, so Power is supplied only during main operation. In the telephone call circuit, a capacitor is connected to the bias terminal, and is charged by receiving the above-mentioned power supply.However, when dial pulses are sent out, make and break are repeated, so the call using the above-mentioned capacitor starts after the make is reached. The DC potential fluctuates until the bias to the circuit stabilizes, and the make voltage value for the make period T1 as shown in FIG.
The period T2 - that is, the make rate - decreases, and when it is significant, the make rate may deviate from the standard. In order to solve this problem, it is necessary to add a special bias circuit for use at the time of make, which often results in the disadvantage of increasing the size and complexity of the configuration.

(Problems to be Solved by the Invention) As mentioned above, with conventional telephones, there is a possibility that the dial pulse make rate may deviate from the standard, and in order to avoid this, the configuration must become larger and more complex. There was a drawback. The present invention was devised in view of the drawbacks of conventional telephones, and its purpose is to provide a telephone whose dial pulse make rate does not deviate from the standard and whose configuration does not become large or complicated. It is to provide.

[Structure of the Invention] (Means for Solving the Problems) In the present invention, when the dial pulse sending circuit is connected to the bias terminal of the calling circuit and the dial pulse sending circuit becomes the make, the dial pulse sending circuit The telephone is equipped with a capacitor for accumulating electric charge from the exchange, and a charging circuit for applying the electric charge from the exchange directly from the dial pulse sending circuit to the capacitor when the dial pulse sending circuit is set up. is.

(Function) According to the above telephone, when the dial pulse sending circuit makes a make, the charging circuit rapidly charges the capacitor and quickly stabilizes the bias, so that the make rate of dial pulses is increased.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of one embodiment of the present invention. In the figure, 1 indicates a central line. A diode bridge 2 is connected to the office line 1, and a transistor 3, which is a dial pulse sending circuit, is connected to the diode bridge 2. Power is supplied to the power supply circuit 4 and the communication circuit 5 by an exchange (not shown) via the office line 1, the diode bridge 2, and the transistor 3. The power supply circuit 4 supplies power to the dial circuit 6, and the dial circuit 6 turns on the transistor 7 when an off-footer occurs, and then turns the transistor 7 on and off based on a dial pulse sending signal given thereafter.

As a result, the base current of the transistor 3 is controlled via the resistor 8, and the transistor 3 is made or broken. The dial circuit 6 outputs a mute signal having a level during the dial pulse sending period via the signal line 9. If there are five dial pulses, this mute signal is a signal as shown in FIG. 2, which falls a little earlier than the first fall of this dial pulse and rises a little earlier than the last rise. The mute signal is applied to the base of transistor 11 via resistor 10 to control on/off of transistor 11. The transistor 11 transfers the electric charge from the exchange that arrives via the transistor 3 to a capacitor 14 via a diode 12 for preventing backflow and a resistor 13.
It acts as a switch for the charging circuit 20 that stores the battery. The capacitor 14 is connected to the bias terminal of the communication circuit 5.

The telephone configured as described above operates as follows when transmitting dial pulses. When off-hook occurs, the dial circuit 6 turns on the transistor 7. As a result, a signal arrives at the base of the transistor 3 via the resistor 8, and the transistor 3 is turned on. Next, the dial circuit 6 is given a signal and turns on and off the transistor 7 by the number of dial pulses to be sent out in order to send out dial pulses. As a result, the transistor 3 is also turned on and off in synchronization, and a dial pulse is sent out.

On the other hand, the dial circuit 6 sends out a mute signal via the signal line 9 as explained in FIG. Thereby, the capacitor 14 is directly charged via the charging circuit 20 during the period when the dial pulse is sent out. Therefore, when the transistor 3 is turned on, the capacitor 14 is rapidly charged, and the bias is quickly stabilized. Therefore, fluctuations in the DC voltage are reduced, and the dial pulse has a large make rate as shown in FIG.

In this way, according to this embodiment, the bias supply capacitor 14 is rapidly charged using the mute signal,
Dial pulse waveform shaping can be easily performed.

Note that instead of the mute signal of this embodiment, a signal that turns on the transistor 11 only when the dial pulse sending circuit (transistor 3) is in the make state may be used. Moreover, if the charging circuit 20 is made to fail when the phone goes from on-hook to off-hook, the start-up time of the call circuit can be shortened.

[Effects of the Invention] As explained above, according to the present invention, the capacitor connected to the bias terminal is charged rapidly and the time until the bias stabilizes is short, so that the dial pulse make rate does not deviate from the standard. , and the structure does not become larger or more complicated.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention, FIG. 2 is a diagram for explaining the operation of one embodiment of the present invention, and FIG. 3 is a diagram of dial pulses sent out by one embodiment of the present invention. FIG. 4 is a diagram showing the waveform of a dial pulse sent out by a conventional telephone front. 1... Office line 2... Diode bridge 3.7.11... Transistor 4... Power supply circuit 5... Call circuit 6... Dial circuit 14... Capacitor 20... Charging circuit Agent Patent Attorney Nori Chika Yudo Sanno -

Claims (1)

[Claims] A capacitor that is connected to the bias terminal of the telephone call circuit and stores the charge applied from the exchange via the central office line through the dial pulse transmitter circuit and the telephone call circuit when the output of the dial pulse transmitter circuit becomes make. and a charging circuit that applies the charge directly from the dial pulse sending circuit to the capacitor when the output of the dial pulse sending circuit becomes make.