KR880000081B1 - Dialing circuit of a wireless telephone - Google Patents

Abstract

In the invention, the tone signals dialed at the key pad of portable unit are transmitted by an antenna and received by a fixed unit to dial correct pulse/tone signals for delivering to a line. Between the output terminal of a discriminator 21 and the input terminal of the regulator 25 are connected a low-pass filter 22, a DTMS-to- keyboard converter 24 and a speaking circuit network 25 in order. The actuation of the tone/pulse switch SW3 applies tone dial signals via the network 25 to the regulator 26, but pulse dial signals are directly applied to the regulator.

Description

TONE / PULSE combined dialing circuit for cordless telephones

1 is a schematic diagram of a dialing circuit of a conventional cordless telephone.

2 is a schematic diagram of a dialing circuit of a cordless telephone of the present invention.

3 is an embodiment of the main circuit of FIG.

The present invention relates to a cordless telephone comprising a mobile portable device and a fixed device for use in connection with an existing telephone line, wherein a tone signal dialed by a key pad of the mobile device is connected through an antenna of the mobile device. The present invention relates to a tone / pulse combined dialing circuit of a cordless telephone for receiving a fixed device so that a pulse signal and a tone signal can be accurately dialed and transmitted to a trunk line.

Conventionally, the dialed dial signal in a portable device has a considerable difficulty in transmitting a dial signal of a rated level to a trunk line in the process of transmitting a dial signal to a trunk line connected to a fixed device through an antenna, and the portable device has a long distance from the fixed device. If there is a problem in the exchange due to the noise (NOISE) could not deliver the correct dial signal to the CO line, the exchange was not able to operate normally, dialing or dialing was not possible.

The present invention solves the above-mentioned drawbacks as described above with reference to the accompanying drawings and the circuit configuration and operation effects as follows.

1 is a schematic diagram of a dialing circuit of a conventional cordless telephone, and when dialed by the keypad 1, a dial signal is output according to the state of the tone / pulse selector switch SW .1 of the tone / pulse dialer 2. FIG. In case of mechanical type according to switching center, pulse dial signal is sent to trunk line, and in case of electronic type, complex frequency signal is output. When the switching center is mechanical, the pulse dial signal output from the tone / pulse dialer (2) is input to the pilot tone oscillator (3) to interrupt the pilot tone oscillator (33).

This pilot tone, which is interrupted for dialing, is applied to the modulator 5, modulated, and then transmitted to the antenna A1 via the high frequency amplifier 6, and the antenna A2 and the high frequency amplifier 7 of the fixed device are replaced. After demodulation in the delimiter (DESCRIMINATOR) 8, it is input to the pilot tone detector 11.

Since the pilot tone detector 11 is made of a PLL, the locking time of the pulse width is different due to an error occurring in the semiconductor manufacturing process. Therefore, in order to compensate for the pulse width, a SCHMIT TRIGGER circuit 12 is added to control the relay 13 with the regenerated pulse dial signal, thereby intermittently turning on the switch (SW .2) connected to the tip terminal of the trunk line. Could hook off, pulse dialing.

However, since the MAKE BREAK RATIO output from the tone / pulse dialer 2 of the portable device causes a time delay due to the locking time in the pilot tone detector 11 of the fixed device, the Schmitt trigger circuit ( 12), but the compensation of the pilot tone detector (11) and the Schmitt trigger circuit (12) IC chip (CHIP) and the locking time according to the input S / N ratio are very difficult. .

When the switching center is electronic, the tone dial signal output from the tone / pulse dialer (2) is input to the modulator (5) so that the high frequency amplifier (6), the antenna of the portable device (A1), the antenna of the fixed device (A2), and the high frequency Through the amplifier 7 and the delimiter 8, the voice amplifier 9 and the hybrid circuit 10 output the dial signal of the complex frequency to the tip and ring terminals of the trunk line. Reproduction of signals at the grit frequency (1209 Hz, 1336 Hz, 1477 Hz) and the low group frequency (697 Hz, 770 Hz, 852 Hz, 941 Hz) was quite difficult due to distortion, and the high and low group frequency pevel The adjustment was tricky.

In addition, when the portable device is far from the fixed device, there is a lot of noise and there is a problem in reproduction of the tone dial signal.

2 is a schematic diagram of a dialing circuit of a cordless telephone of the present invention. The circuit operation in the case of dialing will be described as follows.

When dialed by the keypad 14 of the portable device, the tone / pulse dialer 15 sends a composite frequency signal. The composite frequency signal is a frequency (93-219 Hz) below the voice frequency (300-30400 Hz) band and input to the modulator 18 and modulated, followed by a high frequency amplifier 19, a portable device antenna (B1), and a fixed length antenna ( B2), the high-frequency damper 20, the delimiter 21, the local pass filler 22 is converted into "BINARY 2of8 CODE" and then input to the low-frequency filter to the required frequency, DMT M2 keyboard converter (DIMF TO KEY BOARD CONVERIOR, 23), as shown in Table 1,

TABLE 1

Inverting again, the high-g frequency corresponding to the column COLUMN of the keypad 14 and the low-group frequency corresponding to ROW are made to be logic "0" and applied to the tone / pulse dialer 24. Thus, dialing operation is performed.

If the switching center is mechanical, when the tone / pulse selector switch (SW .3) connected to the tone / pulse dialer 24 of the fixing device is set to the pulse position "P", a pulse dial signal is generated from the tone / pulse dialer 24. Output to tip / ring terminal of CO line, if switchboard is electronic, tone / pulse dialer when tone / pulse select switch (SW .3) connected to tone / pulse dialer 24 of calibration device is set to tone position “T”. The tone dial signal is generated at 24 and is output to the tip and ring terminals of the trunk line through the communication network 25 and the regulator 26.

In this case, even when the S / B ratio of the received dialing signal is not good, the call circuit is muted during dialing so that it is not influenced by noise at all, so that the signal level is stable and the reliability of dialing is put. In addition, the pilot tone detector 28 connected to the output terminal of the delimiter 21 regenerates the complex frequency signal transmitted from the portable device by the signal tone detector 28 and applies it to the relay 29 so that the relay 29 ) Is intermittent with the switch (S / W .4) of the tip terminal of the trunk line to enable on / off hooking.

3 is a block diagram of the main circuit of FIG. 2 according to the present invention.

The complex frequency signal output from the delimiter 21 is low-pass filtered at the required frequency (200 Hz) in the low pass filter 22 composed of the resistor R1 and the condenser C1, and thus the complex frequency receiving circuit chip IC 1 When input to, this circuit chip (IC 1) converts the complex frequency into "binary 2 of 8 code" and then inverts it again from the inverter circuit chip (IC 2) and passes it to the magnetic multiplexer (IC 3). Has the same operation as the keypad 14.

Accordingly, the same logic signals O (OV) and 1 (5V) as those of the keypad 14 are input to the input terminals (pin 3, pin 4, pin 6, pin 21, pin 20, of the tone / pulse dialer circuit chip IC 4). pin 19, pin 18).

At this time, when the tone / pulse selection switch (SW .3) is in the tone position "T", the call circuit chip passes through the resistor (R 21) through the output terminal (PIN 14) of the tone / pulse dialer circuit chip (IC 4). When applied to the input terminal (pin 8) of (IC 5), the tone dial signal is input to the collector of the transistor (Q3) through the output terminal (PIN 13) and output to the emitter to output diodes (D4, D5, D6, D7). , The dial signal is outputted to the tip and ring terminal of the trunk line through the regulator 26 composed of D8).

When the tone / pulse selector switch (SW .3) is in the pulse position "P", the transistors (Q2) and (Q3) are interrupted through the output terminal (pin 24) of the tone / pulse dialer circuit chip (IC 4). The pulse dial signal is output to the tip and ring terminal of the trunk line via the regulator 26.

The transistor Q1 connected to the hook terminal pin22 of the tone / pulse dialer circuit chip IC 4, which is not described, is to make an on / off hook. When the relay 29 operates, the transistor Q1 is turned on. ) And the collector is logical "O".

Accordingly, the tone / pulse dialer 24 operates because the hook terminal pin22 becomes a logic " O " and becomes an off hook.

The voice amplifiers 4 and 17 of FIG. 1 and FIG. 2 are for amplifying the call sound, and the voice signal amplification and frequency bandpass filter 27 of FIG. 2 amplifies and outputs the voice signal output from the delimiter 21. It is to filter the voice frequency band and transmit it to the communication network 25. As in the literature, the present invention operates a tone / pulse dialer in a fixed device with a complex frequency signal dialed by a keypad of a portable device, so that the dial signal is transmitted directly to the tip and ring terminal of the trunk line, thereby providing a mechanical switch or In other words, it is correctly delivered to the electronic exchange.

Claims (1)

A low pass filter 22, a DTS to key between the output terminal of the delimiter 21 and the input terminal of the regulator 26 connected to the trunk line in the fixing device of the cordless telephone as described in the text and shown in the figure. The board converter 23, the tone / pulse dialer 24, and the call network 25 are sequentially connected, and the tone dial signal passes through the call network 25 according to the operation of the tone / pulse selector switch (SW .3). A tone / pulse combined dialing circuit of a cordless telephone, characterized in that a pulse dial signal is introduced into the regulator (26), but the pulse dial signal is directly input to the regulator (26).

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