JPH0194745A - Telephone set - Google Patents

Abstract

PURPOSE:To improve a calling quality by providing a means capable of setting the power source of an active element at either of a telephone line or a direct current power source and securing the direct current power source. CONSTITUTION:An input from circuit terminals L1 and L2 is inputted through a rectifying circuit 3 and a hook switch 7 to a line switch 13. The switch 13 is driven by a dialer IC 10, and its output is inputted to a calling network circuit 8, which is the active element. One of the circuit of the switch 13 is inputted to transistors(TR)1 and 3 of a power source supplying open path 11. The input of the circuit 11 supplies the current from a diode D3 when a VDC exists, and from a diode D2 when it does not exist to the IC10 in an off-hook condition. The power source of the IC10 is normally supplied from a battery VDC, whereas, when a trouble occurs at the direct current power source VDC, the voltage is detected by the IC10, the power source is switched to the circuit 8, and supplied from the telephone set. Thus, the direct current power source is secured, and the calling quality is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a telephone, and more particularly to a power supply thereof.

[Conventional example]

Conventional telephones made up of active elements such as ICs and transistors are powered by either a telephone line or a DC power source such as a battery. In the former case, there is a problem in that the active elements may malfunction due to noise in the telephone line. In addition, this method tends to have serious problems such as adverse effects on the AC impedance or DC impedance of the telephone itself, or related deterioration of call quality, especially in DTMF telephones that require a relatively large drive current. , this phenomenon was noticeable. In the latter case, there is a serious problem in that when the battery or other DC power supply reaches the end of its life or is no longer useful due to a power outage, the active element ceases to operate.

〔the purpose〕

The object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to enable the active elements of a telephone to be driven by current from either a telephone line or a DC power source such as a battery. Another object of the present invention is that when a DC power supply is present and the type of selection signal is a pushbutton PB method using a tone dial signal DTMF, by supplying power supply current from this, it is also possible to use a DP method using a pulse dial signal. The above problem is solved by using a small current as a power source instead of the line, and P
It guarantees the operation of active elements during B transmission, eliminates the negative effects on AC impedance and return loss, prevents deterioration of call quality, and eliminates the need for a DC power supply when a DC power supply is not available. The goal is to make it possible.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram showing the configuration of this embodiment. It is a telephone consisting of active elements such as IC and transistors, and the active elements can be powered by either a telephone line or a DC power source such as a battery. FIG. 3 is a block configuration diagram in the case where when the DC power supply is cut off, the voltage is detected and the telephone line and the stain source are supplied.

In the figure, 1 is the connection terminal L1.2 with the line, and L2.3 is the same...! Even if there is a polarity reversal between 12 and 8.10
and a rectifier circuit added to ensure stable operation of its peripheral circuits; 4,5゜6 is a ring signal detection bridge whose purpose is to notify the speaker of a call when the telephone is on-hook; Ringer, voltage buzzer. 7 is a hook switch that connects the line and the talking circuit side when off-hook; 8
9 is a telephone network circuit which is an active element for making a telephone call; 9 is a handset for making a telephone call; 10 is a dialer IC whose purpose is to transmit a selection signal, and which can transmit both DP and PB;
111 is a power supply circuit for driving 10, and 12 is a mode selection switch s for setting the type of selection signal.
wl, 13 is a line switch which is driven by 1° and sets one line to a release state or a DC capture state when a dial pulse is sent; and 14 is a keyboard.

In the figure, D1 to D3 are rectifier diodes, Trl to Tr3 are transistors, 1111 to R6 are resistors, VDC is a direct current power source such as a battery, D4 is a constant current diode, and SW2 is a DP.
This switch is used when the speaker does not want the 10 to be driven by the line current when the VDC is cut off, or when the speaker does not want the 10 to be driven by the line current when the VDC is cut off. These are 11 components.

In the above configuration, when talking or P
In the case of B transmission, the lines are connected to 8 and 10. If VDC exists here, Tr3 is on, Tr2 is off, and Trl is also off. Then, VDC passes through D3 and supplies current to 10 dialer ICs.

Also, if VDC does not exist, Tr3 is turned off, T
When r2 is on and Tr3 is on, the line current is 2. D
2 and is supplied to 10.

Here, 86 is a high resistance, and the current consumption due to this is assumed to be almost zero. In addition to the above, 1. DI,
It is supplied to IO through D4. Although line current also exists,
This value is also very small, and the impedance of R1, DI, D4) is large. In comparison, it is assumed that the DC impedance of R2°D2 and 8 is minute.

Next, a case will be described in which 8Wl is set to the DP side using the dial pulse method, keyboard 14 is pressed, and 1θ sends out DP. In this case, when the DP is in the make state, the line is connected to the communication network circuit 8, and DC is captured by the break, and the line side exchange determines that it is make, and when the DP is in the break state, the other low DC impedance circuits are connected to the line 8. It is disconnected and the exchanger judges it as a break.

In general, the current consumption of IC is different between DP and PB, such as 1o, P, FB both can send out,
The current consumption during DP is very small, and elements such as R1, DI, and D4, which have a large DC impedance, can operate satisfactorily by being supplied with a small current from the line.

Finally, SWl is set to the FB side, 14 is pressed,
A case where 10 sends an FB will be explained. In this case, it is sent to the line via the PB double signal 8. In this case, a large amount of current is required compared to when DP is used, and if a line is supplied with a stain current to drive this, the current flowing through 8 will decrease and the operation of 8 will become slightly unstable in some cases. There is a possibility that it will become. In addition, most telephone circuits for boat fishing and telephone circuits have the same circuit configuration and current flow path during PB transmission and during a call, as in this circuit. Therefore, in such a configuration, it is not necessary to connect a low DC impedance element to the line during a call, which has a negative effect on the DC impedance, AC impedance, return loss, etc. of the telephone, and deteriorates the call quality. There is a strong possibility that this could lead to Furthermore, if a direct current power source such as a battery is used as the power source during FB, there is a risk that PB transmission will become impossible if this power is cut off.

This circuit normally supplies power to the dialer IC from a DC power source such as a battery, and ensures stable operation of the dialer IC and communication network circuit during FB, and maintains the DC impedance, AC impedance, return loss, etc. of the telephone. It ensures good call quality and enables the dialer IC to send PB even if the direct current from the battery is cut off.
If the speaker does not wish to use the line current to drive the dialer IC when the DC power source such as a battery is cut off,
This makes it possible to ensure good call quality and its narrow characteristics.

As explained above, this embodiment is a telephone that has active elements such as ICs and transistors, and can be powered by either a telephone line or a DC power source such as a battery, and the dialer IC is connected to both the DP and BP. It is equipped with a voltage detection function of the DC power supply, and operates the active element with the current from the telephone line only when the current supply from the DC power supply is cut off during PB mode.
PB momo when P momo and when DC power supply is present
In addition to ensuring stable operation of the telephone network circuit, ensuring DC impedance, AC impedance, and return loss of the telephone, and ensuring good call quality, it also enables PB transmission from the dialer IC even in the absence of a DC power source. I can do that. Furthermore, in this case, if the speaker does not wish to do so, it becomes possible to disable the dialer IC from being driven by the line current.

〔effect〕

As described above, according to the present invention, good call quality can be ensured, and tone dial signals can be sent even in the absence of direct current.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of this embodiment. 3 is a rectifier circuit, 4 is a ring signal detection bridge, 5 is a ringer, 6 is a piezoelectric buzzer, 7 is a hook switch, 8 is a telephone network circuit, 9 is a handset, 10 is a dialer IC, 1
1 is a power supply circuit, 12 is a mode selection switch, 13 is a line switch, and 14 is a numeric keypad.

Claims (2)

[Claims] (1) A telephone having an active element such as a transistor, characterized in that it has a setting means that can set the power source of the active element to either a telephone line or a DC power source such as a battery. (2) It has a means for detecting when the supply of voltage from the DC power supply such as the battery is cut off, and the setting means is configured to use the current from the telephone line according to the output from the detecting means. The telephone set according to claim 1, characterized in that said active element is operated.