JPH02188049A - Telephone set - Google Patents

Abstract

PURPOSE:To detect variation in the electrostatic capacity of a capacitor and to detect hooking by minimizing the distance between metal plate electrodes A and B in the on-hook state of the handset and maximizing the electrostatic capacity Cx. CONSTITUTION:The handset 1 is provided with the metal plate electrode A and a hook detection part 5 is provided with the metal plate electrode B; and they are arranged opposite to each other and the hook detection part 5 is provided with a Wien bridge circuit 6 as an electrostatic capacity detecting means which detects the electrostatic capacity Cx formed between the metal plate electrodes A and B. When the handset 1 is lifted, the capacitor Cx decreases in value, so the Wien bridge circuit 6 becomes unbalanced to generate a potential difference across Rd, and consequently Vd>VREF, so that the output is '1'. Consequently, the hook detection is enabled without any mechanism switch.

Description

[Detailed Description of the Invention] [Summary] This invention relates to a telephone, and particularly to a hook detection device by raising and lowering the handset of the telephone, and the present invention relates to a hook detecting device for detecting a hook by raising and lowering the handset of the telephone, and the present invention relates to a hook detecting device for detecting a hook by raising and lowering the handset of the telephone. The purpose of hook detection is to detect changes in the capacitance of a capacitor, and the hook detection part of the hand center and the phone body are placed facing each other to form a flat plate capacitor with capacitance. and a capacitance detection means for detecting a variation in capacitance of the flat capacitor due to a change in on-hook/off-hook of the hand cent.

[Industrial application field]

TECHNICAL FIELD The present invention relates to telephones, and more particularly to a hook detection device for raising and lowering the handset of a telephone.

Since telephones are used by an unspecified number of subscribers, they are desired not only to be inexpensive but also to be easy to use and handle for a long time, and to have stable quality.

The present invention improves the hook detection method in order to realize a telephone that operates stably over a long period of time.

[Conventional technology]

FIG. 4 is a diagram showing a hook detection method using a conventional mechanical switch. In the figure, l is the handset of the telephone. Further, 11 to 16 are configurations for hook detection, 11 is a hook switch housing, and I2 is a handset 1.
13 is a contact drive part having a movable part 13a that moves up and down together with the handset 1, and 15 is a fixed part 13.
This is a rod that passes through b and is supported by a spring 14, and moves up and down as the handsera I-1 moves up and down, and its tip abuts the hook switch contact 16 to open and close the hook inch contact 16.

Now, when the handset 1 is placed on the footer, that is, when the handset 1 is placed on the phone body, the cover 12 and the movable contact 13a of the contact drive unit 13 are released from contact with each other, opening the hook switch contact 16, and vice versa. When the handset 1 is taken off-hook, that is, when the handset 1 is lifted up from the phone body 6, the movable contact 1 of the lid 12 and the contact drive unit 13
3a moves in the direction of contact and connects the hook switch contact 16.
close it.

That is, hook detection is performed by providing a hook switch contact 16 that opens or closes each time the handset l goes on-hook or off-hook, and uses a signal passing through the hook switch contact 16 as a contact output.

[Problem to be solved by the invention]

Therefore, the conventional hook detection method using a mechanical switch requires a complicated structure and mechanism between the handset 1 and the lid, and is not economical.

SUMMARY OF THE INVENTION An object of the present invention is to provide a telephone that performs hook detection by detecting changes in the capacitance of a capacitor formed on a metal plate electrode provided opposite to each other between the telephone hand center and the telephone main body. shall be.

[Means to solve the problem]

FIG. 1 is a diagram showing the basic configuration of the present invention.

In the figure, reference numerals 2 and 3 are metal plate electrodes A and B, which are arranged opposite to each other on the hook detection part 5 of the handset 1 and the telephone body, respectively, to form a flat plate capacitor (4) with capacitance. and 6 is a capacitance detection means, which is connected to the hook detection section 5 in order to detect the amount of variation in the capacitance Cx of the flat plate capacitor 4 due to changes in on-hook/off-hook of the handset 1. It is built-in.

This capacitance detection means 6 is configured to obtain the detection portion horn of the hook from the amount of variation in the capacitance 1 c x of the flat plate capacitor 4 .

[For production]

In the present invention, as shown in FIG. 1, when Hunt 2 set 1 is on-hook, the distance between metal plate electrode A of 2 and metal plate electrode B of 3 is minimized to maximize capacitance C. The capacitance detection means 6 outputs "l". When the handset 1 is in the off-hook state, the distance between the metal plate electrode A of 2 and the metal plate electrode B of 3 is maximized, and the capacitance CX is minimized to detect electrostatic capacitance. The capacitance detection means 6 outputs 0゛.

Therefore, the hook can be detected by the outputs 1' and 0' from the capacitance detection means 6.

〔Example〕

FIG. 2 is a diagram showing a circuit configuration of an embodiment of the present invention.

In the figure, 1 is a handset, which has 2 metal plate electrodes A built-in. Further, 8 is the main body of the telephone, which includes the metal plate electrode B of 3 and the Wien bridge circuit 6 which is the capacitance detection means.
It consists of a hook detection section 5 and a telephone control section 7.

In the present invention, as shown in FIG. 2, two metal plate electrodes A are provided on the handset 1, and three metal plate electrodes B are provided on the hook detection section 5, which are arranged facing each other. The hook detection unit 5 is provided with a Wien bridge circuit 6 as a capacitance detection means for detecting the capacitance CX formed between the metal plate electrode A and the third metal plate electrode B.

FIG. 3 is a diagram showing the circuit configuration of the hook detection section of the present invention. The capacitance Cx shown in the figure is 2 metal plate electrodes A and 3
represents the capacitance of the flat plate capacitor 4 formed by the metal plate electrode B of . Also, resistors R+, R2, R3, R
a, Ra, capacitor CX, CI and oscillator 50
A Wien bridge circuit 6 is constructed. The potential difference induced across Ra when the Wien bridge circuit 6 becomes unbalanced is amplified by the amplifier 51, diode D, and capacitor C1, half-wave rectified, and smoothed to produce a DC voltage (2).

is converted to This DC voltage ■6 is the threshold voltage V□
, are compared in the comparator 52. When the handset 1 is placed, the Wien bridge circuit 6 is in an equilibrium state, the potential difference between both ends of R4 becomes Ov, and the output of the comparator 52 becomes 0°. When the handset 1 is picked up and lifted, the value of the capacitor CX becomes smaller and the Wien bridge circuit 6 becomes unbalanced, creating a potential difference across R4. As a result, ■4V 1l
It becomes EF and the output becomes '1'. Note that these relationships are expressed as follows.

R1/R2= R3/R4+ C1/CXωzCICX
R3R4=1 where ω indicates the frequency of the oscillator 50.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, hook detection is possible without a mechanical switch, and the mechanism of the telephone can be simplified.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the principle configuration of the present invention. FIG. 2 is a diagram showing the circuit configuration of an embodiment of the present invention. FIG. 3 is a diagram showing the circuit configuration of the hook detection section of the present invention. 1 is a diagram showing a hook detection method using a conventional mechanical switch. In the figure, 1 is a handset, is a metal plate electrode A1 is a metal electrode plate B1 is a flat capacitor, is a hook detection unit, is a capacitance detection means (Wien bridge circuit), and is a diagram of the invention A in Figure 7. $NEIJln-gway(Bodj'+[MIjlAs:
t-Tr'J No. 2 Figure 4-1
Figure diagram

Claims (1)

[Claims] Handset (1) and hook detection section (2) of the telephone main body
are arranged facing each other, and the capacitance (C_x)
Metal plate electrode A forming a flat plate capacitor (4) having
(2) and metal plate electrode B (3), and the handset (
A telephone set comprising: capacitance detection means (6) for detecting the amount of variation in the capacitance (C_x) of the flat plate capacitor (4) due to the on-hook/off-hook change of 1).