CN100508529C

CN100508529C - An automatic hand-up device of telephone and its control method

Info

Publication number: CN100508529C
Application number: CNB200610105135XA
Authority: CN
Inventors: 屈朋伟; 李辉; 黄鹤; 桂大江
Original assignee: Northwestern Polytechnical University
Current assignee: Northwestern Polytechnical University
Priority date: 2006-12-07
Filing date: 2006-12-07
Publication date: 2009-07-01
Anticipated expiration: 2026-12-07
Also published as: CN1997040A

Abstract

This invention discloses one telephone automatic hanging device, which comprises one triode, three resistances, one capacitor and one control chip, wherein, the telephone audio power amplifier output signal is connected to microphone through one insulator capacitor with other path through limit resistance to triode base electrode; the triode emission electrode is connected to earth and integral electrode is connected to I/O interface of control chip by series of one upper pull resistance power anode. This invention also provides one control method of the device.

Description

A kind of automatic hand-up device of telephone set and control method thereof

Technical field

The present invention relates to communication technique field, especially a kind of communications user terminal equipment and control method thereof.

Background technology

Along with telephonic communication development of technology and development, the function of telephone set is more and more, and it is more and more convenient to use, and most phones all provide the hand-free call function.But in actual life, often the back phone fails in time to place hook state because user's carelessness causes conversing, perhaps misoperation and cause phone connect automatically the back permanent, be in talking state for a long time, thus cause this phone because of the line is busy for a long time can't incoming call.Both, also caused the user to pay high cost of the phone call for no reason for the user makes troubles.At present, the telephony product that can realize the automatic hand-up function under hand-free function is seldom arranged on the market.The phone that can realize the automatic hand-up function few in number has all adopted special integrated chip to detect busy-back signal, the principle of these chips is the signals that the peak tone signal converted to high-low level, the clock of use itself detects busy-back signal, export to control chip, thereby realization automatic hand-up function.But, such special integrated chip, market is not popularized, and purchase is got up very inconvenient, and its price is also mostly higher, and the cost of telephone set is increased greatly.

Summary of the invention

In order to overcome the higher shortcoming of prior art cost, the invention provides a kind of automatic hand-up device of telephone set, this installs, and not only circuit is simple, and cost is very low, can detect busy-back signal reliably, realizes phone automatic hand-up function.

The present invention includes a triode, little resistance resistance, current-limiting resistance, big resistance pull-up resistor, capacitance and a control chip.The output signal of audio-frequency power amplifier that is used to drive loud speaker in the telephone set is divided two-way after by a capacitance, and the resistance of a little resistance of series connection of leading up to connects loud speaker, and another Lu Jingyi current-limiting resistance is connected to the base stage of triode.The grounded emitter of triode, collector electrode connect the I/O mouth of control chip, and the resistance of the big resistance of connecting is to positive source, and this resistance is called pull-up resistor, when triode by the time make the I/O input high level of control chip.

Circuit enters operating state behind the telephone set off-hook, and triode ends when audio-frequency power amplifier absence of audio signal is exported, and the collector electrode output high level of triode has imported high level just for the I/O mouth of control chip.When audio-frequency power amplifier has audio signal output and this audio signal level amplitude greater than the triode conducting voltage, the triode conducting, the collector electrode output low level of triode has imported low level just for the I/O mouth of control chip.After the variation Be Controlled chip sampling of the high and low level of transistor collector, judge by control chip whether busy tone arrives, just carry out the on-hook instruction if control chip detects busy tone, thereby realize the automatic hand-up function.At the resistance of a little resistance of loud speaker place branch road series connection is in order to improve audio signal level, and triode can obtain enough big conducting voltage when guaranteeing that busy tone arrives.

The present invention also provides a kind of control method of described automatic hand-up device, may further comprise the steps:

A) control chip is with busy tone number of times zero clearing in the register;

B) collector electrode by triode detects audio signal, judges whether busy tone, if control chip adds 1 with busy tone number of times in the register, if not, return step a);

C) control chip judges whether the busy tone number of times reaches set point number in the register, if control chip is carried out on-hook, if not, return step b).

The invention has the beneficial effects as follows, only just can the busy-back signal in the telephone line be detected with a triode that saved the special integrated chip in the traditional circuit, circuit is simple, it is convenient to realize, components and parts are bought easily, and cost reduces greatly.

Further specify of the present invention below in conjunction with drawings and Examples.

Description of drawings

Fig. 1 is the circuit diagram of automatic hand-up device of the present invention;

Y represents loud speaker among the figure, and VCC connects positive source, and V represents triode.

Fig. 2 is the flow chart of control method of the present invention.

Embodiment

With reference to Fig. 1, embodiments of the invention comprise a NPN type triode V, three resistance R 1, R2, R3, an electrochemical capacitor C and a control chip.

Control chip of the present invention is selected single-chip microcomputer 8051 for use, and establishing the I/O mouth is the P3.7 mouth, and VCC represents the positive source of telephone set network.Audio power amplifies after the capacitance C of output signal through one 220 μ F, output signal is divided into two-way, one the tunnel receives loud speaker through one 10 Ω resistance R 1, another Lu Jingyi 1K Ω current-limiting resistance R2 receives the base stage of 2SC9014 type triode V, the grounded emitter of triode V, collector electrode connect P3.7 mouth and 5.1K Ω resistance R 3 to positive source VCC of single-chip microcomputer 8051.

Circuit enters operating state behind the phone off-hook, behind the output signal process capacitance C of audio-frequency power amplifier is the AC audio signal, this AC audio signal divides two-way, and one the tunnel through 10 Ω resistance R, 1 back promotion loud speaker Y, and triode V is removed to control through resistance R 2 in another road.Because the conducting voltage of the P-N of silicon triode knot is 0.7V, so triode V conducting when the base voltage of triode V is not less than 0.7V, its collector electrode-emitter interpolar pressure drop diminishes the collector electrode output low level.Otherwise, when the base voltage of triode V during less than 0.7V, collector electrode output high level.Because the noise signal level of audio-frequency power amplifier output is very little, usually all much smaller than 0.7V, deficiency is so that triode V conducting, thereby avoided misleading of triode V.

As shown in Figure 2, begin to carry out this program behind the phone off-hook, write down the busy tone number of times by a data register of single-chip microcomputer 8051.So that accurately detect busy-back signal, single-chip microcomputer 8051 must be consecutively detected 3 busy-back signals can on-hook, if once detected to non-busy-back signal register clear 0 in 3 times and detect again, promptly jump to the first step a) by single-chip microcomputer 8051.Concrete controlled step is:

A) register is clear 0, and record busy tone number of times is 0 time;

Whether b) detect the audio signal that collects from the P3.7 mouth of single-chip microcomputer 8051 is busy-back signal, if register adds 1 and enter next step, if not, detect again and return previous step a);

C) if be consecutively detected busy-back signal 3 times, then the value of register is 3, and the value that determines register when program is 3 just to carry out the on-hook instruction, otherwise returns the second step b), detect busy-back signal again.

The present invention only just can detect the busy-back signal in the telephone line with a triode, has saved the special integrated chip in the traditional circuit, and circuit is simple, and it is convenient to realize, components and parts are bought easily, and cost reduces greatly.Simultaneously, the present invention has adopted simple and effective control method, well combines with control device of the present invention, has guaranteed the reliably working of device.

Claims

1, a kind of automatic hand-up device of telephone set, comprise a triode, one 10 Ω resistance, a current-limiting resistance, a 5.1K Ω resistance, a capacitance and a control chip, it is characterized in that: the output signal of audio-frequency power amplifier that is used to drive loud speaker in the telephone set is divided two-way after by described capacitance, the described 10 Ω resistance of series connection of leading up to connect loud speaker, another road is connected to the base stage of described triode through described current-limiting resistance, the grounded emitter of described triode, collector electrode connects the I/O mouth of described control chip, and the described 5.1K Ω resistance of connecting is to positive source.

2, according to the automatic hand-up device that utilizes the described a kind of telephone set of claim 1, it is characterized in that: described control chip is selected single-chip microcomputer 8051 for use.

3, a kind of control method according to the described automatic hand-up device of claim 1 is characterized in that comprising the steps:

(a) control chip is with busy tone number of times zero clearing in the register;

(b) collector electrode by triode detects audio signal, judges whether busy tone, if control chip adds 1 with busy tone number of times in the register, if not, return step (a);

(c) control chip judges whether the busy tone number of times reaches set point number in the register, if control chip is carried out on-hook, if not, return step (b).