JPH067606Y2 - Charge pulse removal device - Google Patents

Description

[Detailed Description of the Invention] (Industrial field of application) The present invention is located between a telephone line with a charging pulse and a communication device such as a facsimile, and normally operates the communication device by removing the charging pulse from the telephone line. The present invention relates to a communication device line fee charging pulse removing device.

(Prior Art) Conventionally, as shown in FIG. 2, a charging pulse removing device has a telephone line 1 with a charging pulse and a communication device 2 such as a facsimile.
Will be installed between In this device, the signal detection circuit 3 is a circuit that detects a ringing signal sent from the transmission side through the telephone line 1 and sends a detection signal. The control circuit 4 sends a switching signal in response to a mode signal issued when the transmission mode of the communication device 2 is selected by the user at the time of transmission or a detection signal from the signal detection circuit 3 at the time of reception. It is a circuit to do. The charging pulse removing circuit 5
A transformer T having capacitors C ₁ and C _{2 respectively} connected to the primary and secondary sides, a diode bridge D connected in parallel to the transformer T, a reactor L connected in series to the diode bridge D, and a reactor. And a diode Df connected in antiparallel to L. In the charging pulse removing circuit 5, the communication signal is transmitted to the communication device 2 side through the transformer T, but the charging pulse is separated to the diode bridge D side. The switches 6 and 7 receive the switching signal from the control circuit at the time of transmission, insert the charging pulse removing circuit 5 between the telephone line 1 and the communication device 2, and directly connect the two at the time of reception.

(Problems to be Solved by the Invention) In the above-described conventional charging pulse removing device, since the charging pulse removing circuit 7 includes the diode bridge D, the reactor L and the diode Df, the circuit becomes complicated and the cost becomes high. Further, there is a problem that it becomes an obstacle to downsizing of the device.

Therefore, an object of the present invention is to provide a charging pulse removing device which has a simple circuit configuration and can be obtained at low cost.

(Means for Solving the Problems) In order to solve the above problems, in the present invention, there is provided a charging pulse removing device provided between a telephone line 1 with a charging pulse and a communication device 2, which is a communication device 2. Control circuit 4 for receiving a transmission mode signal from the telephone and transmitting a switching signal, a charging pulse removing circuit 10 for removing a charging pulse from the telephone line 1 and transmitting a communication signal to the communication device 2, and a control circuit 4 at the time of transmission. The charging pulse removing device is composed of the switches 6 and 7 which insert the charging pulse removing circuit 10 between the telephone line 1 and the communication device 2 in response to the switching signal from the charging pulse removing circuit 10. Among the signals sent from the line, a transformer T for transmitting a communication signal for AC and blocking the entrance of a charging pulse for DC, a resistor R for dropping the charging pulse on the primary side of the transformer T, and a communication A DC voltage power supply E for maintaining the secondary side voltage of the transformer T at the telephone line voltage during a normal call is provided so as to carry a signal.

(Operation) When data is transmitted by the communication device 2 through the charging pulse removing device of the present invention, the control circuit 4 receives the mode signal based on the selection of the transmission mode of the communication device 2 by the user, and switches the switching signal. Send to vessels 6 and 7. Switch 6,
7 receives the switching signal and switches the connection so that the charging pulse removing circuit 10 is inserted between the telephone line 1 and the communication device 2. During the communication, the charging pulse removing circuit 5 operates on the telephone line 1.
Only the AC component of the signal transmitted via the transformer T is transmitted to the communication device 2 via the transformer T. That is, since the charging pulse that is intermittently sent together with the communication signal is DC, it is not transmitted to the secondary side of the transformer T. The voltage component of this charging pulse drops through the resistor R. The weak induction noise corresponding to the rising and falling of the charging pulse is transmitted to the secondary side of the transformer T, but this does not cause any practical obstacle to the function of the communication device. The communication signal output to the communication device 2 side via the transformer T is increased to the telephone line voltage at the time of a normal call by the voltage from the DC voltage power supply E and transmitted to the communication device 2.

(Embodiment) An embodiment of the present invention will be described with reference to FIG. Incidentally, in the figure, the same components as those of the conventional one shown in FIG.

In the figure, the switch 6 on the telephone line 1 side is the telephone line 1
Contact S for connecting the communication line between the communication device 2 and the communication device 2
₁ and S _2, and contacts S ₃ and S ₄ for connecting a communication line between them via the charging pulse removing circuit 10. Similarly to the switch 6, the switch 7 on the communication device 2 side also
It has contacts S ₅ , S ₆ , S ₇ , and S ₈ .

Transformer T and capacitor C of charging pulse removal circuit 10
₁ and C ₂ are for transmitting a communication signal which is an AC voltage as in the conventional case, but the capacitor C ₁ is not essential among them. A resistor R is connected in parallel to the capacitor C ₁ on the primary side of the transformer T. Therefore,
The charging pulse, which is a DC voltage, is not transmitted to the secondary side. On the secondary side of the transformer T, a constant voltage for carrying a normal call signal on the telephone line is applied. Therefore, in order to create a signal line in the same state as this, a DC constant for maintaining the telephone line voltage during a normal call is applied. The voltage power source E is connected with the negative electrode side grounded.

When data is transmitted by the communication device 2 via the charging pulse removing device, when the user selects the transmission mode of the communication device 2, a mode signal is sent from the communication device 2 to the control circuit 4 based on this selection. Sent. When the control circuit 4 receives this mode signal, it sends a switching signal to the switches 6 and 7. At this time, the switch 5 closes the contacts S ₃ and S ₄ , and the switch 6 closes the contacts S ₇ and S ₈ to connect the charging pulse removing circuit 10 between the telephone line 1 and the communication device 2. During communication, the charging pulse removal circuit 10 transmits the communication signal sent through the telephone line 1 to the communication device 2 through the capacitors C ₁ and C ₂ and the transformer T. The charging pulse sent together with the communication signal for each talk flow as a DC component through the resistor R. However, it is not transmitted to the secondary side of the transformer T. Corresponding to the rising and falling of the charging pulse, a weak induction noise is induced on the secondary side, but this does not cause a practical obstacle to the function of the communication device. The communication signal transmitted to the secondary side of the transformer T is maintained at the telephone line voltage during a normal call by the voltage from the power source E, and the communication device 2
Be transmitted to. Therefore, the communication device 2 receives only the communication signal from which the charging pulse has been removed. When the communication device 2 receives data, the signal detection circuit 3 detects a ringing signal sent from the transmission side through the telephone line 1 and sends the detection signal to the control circuit 4. In response to this, the control circuit 4 sends a switching signal to the switches 6 and 7. At this time, since the charging pulse is not sent from the telephone line ₁ , the switcher 5 closes the contacts S ₁ and S ₂ , and the switcher ₆ closes the contacts S ₅ and S ₆ to make a call without the charging pulse removing circuit 10. The line 1 side and the communication device 2 side are connected.

Although the present apparatus is configured separately from the communication device 2, it can be incorporated in the communication device 2.

(Effect of the Invention) As described above, according to the present invention, the charging pulse removing device is provided between the telephone line 1 with the charging pulse and the communication device 2, and the transmission mode signal from the communication device 2 is transmitted. A control circuit 4 for receiving and transmitting a switching signal, a charging pulse removing circuit 10 for removing a charging pulse from the telephone line 1 and transmitting a communication signal to the communication device 2, and a switching signal from the control circuit 4 for transmission. The charging pulse removing device is composed of the switches 6 and 7 for inserting the charging pulse removing circuit 10 between the telephone line 1 and the communication device 2.
0 is a transformer T that transmits a communication signal for an alternating current among the signals transmitted and blocks the entrance of a charging pulse for a direct current, a resistor R that drops the charging pulse on the primary side of the transformer T, and a communication Since it is equipped with a DC voltage power supply E that keeps the secondary voltage of the transformer T at the telephone line voltage during a normal call so as to carry signals, it is possible to connect communication equipment to a telephone line with a charging pulse without hindering the function. Moreover, since the circuit configuration is simple and a diode bridge or the like is not required unlike the conventional case, it is possible to downsize the device, and it is possible to obtain the effect that the manufacturing is easy and the cost is low.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a charging pulse removing device according to the present invention, and FIG. 2 is a circuit diagram of a conventional charging pulse removing device. 1 ... Telephone line with charging pulse, 2 ... Communication equipment, 3 ...
... Signal detection circuit, 4 ... control circuit, 5 ... billing pulse removal circuit, 6,7 ... switch, T ... transformer, E ...
DC voltage power supply.

Claims (1)

[Scope of utility model registration request] 1. A billing pulse removing device provided between a telephone line with a billing pulse and a communication line, the billing pulse removing a billing pulse from the telephone line and transmitting a communication signal to a communication device. A removal circuit and a switching device that receives a switching signal from the control circuit during transmission and inserts a charging pulse removal circuit between the telephone line and the communication device, and transmits a communication signal to the pulse removal circuit. A transformer that blocks the entrance of the charging pulse that is a direct current component, a resistor that drops the charging pulse on the primary side of the transformer, and the secondary side voltage of the transformer is maintained at the telephone line voltage during normal communication so as to carry communication signals. A charging pulse removing device comprising a DC voltage power supply.