JP2835968B2 - Telephone circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Industrial application field to which the present invention pertains The present invention relates to a telephone set connected in parallel to a pair of lines.
The present invention relates to a telephone circuit capable of calling another telephone connected in parallel from a telephone during a call.

(2) Conventional technology and its problems Conventionally, when a plurality of telephones are connected to a pair of lines and used, functions such as inter-call and transfer are realized by a home telephone or the like. There is an increasing tendency to select a single telephone according to personal preferences such as necessary functions and design and each room, and to use them in parallel connection. As means for realizing functions such as mutual calling and transfer between telephones connected in parallel to a pair of lines, there is a configuration shown in FIG. 5 shown in Japanese Patent Publication No. 60-51297, for example. The DC loop is periodically continued by the middle telephone so as to drive the tone ringer circuit of the telephone connected in parallel and make a call.

However, in this configuration, the DC loop is interrupted by the telephone during a call, so that the pulse generated by this interruption is
It is transmitted as click noise, for example, to a caller who is waiting for reading, causing unpleasant thoughts.Also, depending on the period of the continuous pulse, the switch malfunctions and sends a pulse signal other than a dial signal to the line. In this case, there is a problem that the attenuation of unnecessary signals outside the communication band, which is a requirement of the technical standards, is insufficient.In addition, when there are a plurality of telephones connected in parallel, reading can be performed individually. Since the call cannot be made, all the telephones ring due to the call, and there has been a problem that it is necessary to determine which telephone to call based on the caller's cycle and number of times.

(3) Object of the Invention The present invention provides a telephone circuit for realizing a telephone capable of making individual calls between telephones connected in parallel to a pair of lines.

(4) Configuration of the Invention In order to achieve this object, the present invention is configured as follows.

That is, the parallel-connected telephones are provided with means for setting their own numbers, and a means for forming a data string by dial input for selectively calling the parallel-connected telephones and a means for decoding a data signal are provided. The telephones connected in parallel are called individually, and the data signal is composed of a pulse train having a repetition frequency outside the communication band, so that the attenuation of unnecessary signals outside the communication band according to the technical standards can be satisfied. Has been made.

Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 shows an embodiment of the present invention, in which 1 is a line composed of lines L ₁ and L ₂ , 2 is a switch for setting a self-number, 3 is a control circuit for generating, decoding and controlling a telephone, 4 Is a circuit for transmitting a data signal in which a unit code is formed at a repetition frequency outside the speech frequency band, 5 is a circuit for detecting a data signal, 6 is a data signal reproducing circuit, 7 is a dial input section, 8 is a ring tone circuit, 9 is Hold circuit, 10 is the call circuit, 11 is the handset,
12 is a transmitter, 13 is a ringing circuit for detecting a call signal, 14 is a battery, 15 is a buzzer, 16 is a hook switch, 17 is a telephone during a call, and 18 and 19 have the same circuit configuration as 17 FIG. 2 is an example of a data signal reproducing circuit, and FIG. 3 is a time chart showing the operation thereof.

 The operation of this embodiment will be described.

(Incoming operation)

The incoming call operation of this embodiment is as shown in FIG. 4A, and a call can be started by on-hook by incoming call.

(Outgoing operation)

The outgoing call is as shown in FIG. 4B, and the call is started by the on-hook of the other party corresponding to the dial operation.

[Paging operation during a call]

The operation at the time of calling during a telephone conversation according to the gist of the present invention is as shown in FIG.
(D). These are described below with reference to FIGS.
2, a more detailed description will be given with reference to FIG.

From the dial input unit 7 of the telephone set 17 held by the hold circuit 9, the called telephone set 18 connected in parallel is connected.
When the telephone number of (or 19) is input, a data string OUT as shown in FIG. 3 is output from the control circuit 3 constituted by the CPU using the unit code (FIG. 3L) of the repetition frequency outside the communication band. It is output and sent out to the line 1 as a data signal from the data signal sending circuit 4.

In the telephone set 18 (or 19) connected in parallel, the data signal transmitted on the line 1 is detected as a differential output by the data detection circuit 5 having a pulse transformer in this case, and [output B] is obtained. . This output enters the data signal reproducing circuit 6, and in consideration of the case where the connection polarities of the _one line L ₁ and L ₂ are reversed, the change in the signal is made by the transistors Q ₁ and Q ₂ which are configured to correspond to both polarities. The data is taken in and is reproduced as received data [SI] by the IC ₃ via the noise elimination circuits IC ₄ and IC ₁ . The reproduced data signal [SI] is supplied to the control circuit 3
When the decoded data signal matches the own telephone number set by the dial input unit 7, a ring tone is generated by the ring tone circuit 8. When the called telephone 18 (or 19) goes off-hook, the called telephone 17 is released from hold and the call is transferred to another telephone 18.
(Or 19).

Here, in general, the number of telephones that can be connected to one line is limited to about three. Therefore, the data signal is a data string, for example, telephone numbers 1 [0001], 2 [1001], 3 [0101]
The telephone number 3 is generally set to [101] without following the 22-ary notation as in [0011]. this is,
This is to avoid shifting the frequency spectrum of the data signal to the low band due to the continuation of "1" in the adjacent time slot of the data train, and also an effective method to satisfy the attenuation of unnecessary signals outside the speech band. It is.

Further, it is preferable that the transmission level of the data signal to the line 1 is as low as possible. For this reason, receiving amplifiers Q ₁ and Q ₂ are provided to take into account attenuation of unnecessary signals outside the communication band. Here, the repetition frequency of the unit code of the data signal is
Although it is set to 27 KHz, it goes without saying that the repetition frequency is not limited to achieving the same purpose. The specific configuration and operation of the circuit shown in FIG. 5 will be described.

Operation of the incoming circuit The incoming circuit is always connected to L ₁ -L ₂ , and when an incoming signal is sent, it is full-wave rectified by the CD ₂₄ and passed through the LED to the VCC of the tone ringer IC, and at the same time TR ₉ Turn ON to drive the buzzer S (sounder).

In addition, the incoming call sensitivity and incoming sound quality are each 2 by DIP-SW.
The ring volume can be switched to three stages by the slide SW.

CD ₃ is an LED reverse voltage protection diode, and CD ₂₀ is a tone ringer IC overvoltage protection varistor. TR ₉ is to prevent the tone ringer IC from becoming a load when sounding BEEP or the like.

Electronic Hook Circuit a) Activation by Hook SW When the handset is lifted from the standby state, the AB, CD contacts of the hook switch HS are closed, and the line closing circuit LS is operated by the make of AB. As a result, current is supplied to the speech network NW (IC), and a DC loop is formed. Also the contacts C-D of the hook switch HS is the make, the microcomputer CPU ▲ ▼ is through TR ₁₃ "L"
The microcomputer CPU detects the off-hook mode, sets LOOP to "H", supplies a current to the line connection circuit LS, and holds the operation.

It should be noted, TR ₁₃ for the CPU malfunction prevention of when you start from the initial state, the input signal after the V _DD rises to complete ▲
The HS is set to "H" when the line is disconnected while off-hook so as to prevent the loss of current due to internal pull-up.

b) Activation by SP button When the SP button in the keypad described below is pressed in the standby state, the microcomputer CPU changes from the sleep mode to the operation mode and starts the key scan. Here, when the depression of the SP button is detected, LOOP is set to “H”, the line connection circuit LS operates, and a DC loop is formed.

Dial circuit a) DP transmission circuit When the dial button is pressed in the DP mode, the DP repeats HL by the number corresponding to the depression. As a result, the line connection circuit LS repeats OFF-ON.

b) PB transmission circuit When the dial is pressed in the PB mode, 2
The frequency is output from TONE-OUT of the microcomputer CPU. This is divided by a resistor on the way, and one is BI of the speech network NW
Is received by the receiver or speaker as a PB confirmation sound, and the other is input to the MFI of the speech network NW and transmitted to the circuits L ₁ and L ₂ via the VL and the circuit closing circuit LS.

Hold circuit When the hold button HD is pressed during a call, the microcomputer CPU detects it and sets HDA to “H”. This allows V _{DD to be} added to the melody IC.
The voltage between -GND is secured and the melody is output from the melody IC MO. Subsequent transmission and confirmation sounds are the same as PB transmission.

At this time, even if the handset is placed, the microcomputer CPU
The line is not interrupted because the LOOP of "H" holds "H".

KEY TONE When the circuit and BEEP circuit microcomputer CPU KT and BEEP is output at 2 KHz, the transformer T ₃ Repeat TR ₁₈ are each ON-OFF accordingly
2KHz signal is given to 600Ω side of. As a result, the voltage becomes approximately three times as high as that on the 6KΩ side, and the buser S (sounder)
Drive.

Power circuit E of the power supply circuit phone is than four configurations of the power supply E ₄ ...... low current circuit ₃ ...... DP during make-backup power supply E when power E ₂ ...... stand by E ₁ ...... AAA batteries During normal operation, it is maintained at about 3 V by a low-current circuit of E4, and AAA batteries are mainly used as a power supply for memory backup.

R-UP circuit The output end RUP of the microcomputer CPU becomes high (H) -low (L) by pressing the receiving volume switching button UP, and the amount of negative feedback from the RC of the speech network NW is used as the receiving gain adjusting circuit R-.
Since the gain of the amplifier is increased via the UP, the reception volume is increased.

In addition, the reception sound volume is reset in the case of dialing, ending the call, holding, and the like, and returns to the state of low reception sound volume.

Imaginary ground (IM-GND) circuit After the LOOP of the microcomputer CPU is closed and the transfer signal is received, the microcomputer CPU momentarily sets the IM-GND circuit to L. At this time, the setting by the DIP-SW (for example, as shown in the figure) TEL ₁ / TE
L ₂ , DP / PB, 20/10, OAP / OFF) is read by the microcomputer CPU, and D
Performs the function operation according to the IP-SW setting.

Branch Bell Circuit a) Sending Circuit When the buttons of the dials 1 to 3 are pressed in the hold mode, an output signal corresponding to the dial button is output from the SO of the microcomputer CPU. At the same time, a synchronization signal is output from SCK. SCK inversion signal and SO pending transfer unit HT
AND circuit AND output is input to TR17 base and V
The transmission pulse from L is transmitted to the lines L ₁ and L ₂ via the line closing circuit LS.

b) Receiving circuit Other telephone (not shown) of the branch partner in the standby state
When from VL sends a transmission pulse, the primary side of T ₁ through C ₅₂ (1
10Ω). Then about 1 on the secondary side (11KΩ)
It appears as a voltage of 0 times and a signal is sent to the hold transfer unit HT.

In the hold transfer unit HT, to detect that the time difference between the rising signal and the rising signal is the width of the pulse, the window is opened by the signal input first, and the window is opened only within a predetermined time (pulse width). We do not let signal pass. As a result, noise is removed. Waveform shaping of the passed signal is compared with SCK (system lock) to recognize data.

c) Transfer data Transfer data is sent according to the pattern shown in Fig. 6 (a) and is received at the timing shown in Fig. 6 (b) when data matches within the ISEC with a probability of 2/3, and reception is OK and BEEP is output. I do.

Configuration of Keypad The keypad has the following configuration as an example.

(5) Effects of the present invention As is apparent from the above description, according to the present invention,
Individual calls can be made between telephones connected in parallel to a pair of lines, and an operation like a home telephone can be expected.
In addition, the same effect can be obtained even when the telephone is connected to a general public line such as an office line, and the usability when a plurality of telephones are connected in parallel is remarkably improved.

It can be said that this effect is remarkable in that the home telephone requires two pairs of lines, but the same effect can be obtained with a pair of lines.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIGS. 2 and 3 are circuit diagrams showing a configuration example of a data signal reproducing circuit used in the present invention and a time chart showing its operation, and FIG. 4 shows the operation of the present invention. FIG. 5 is a circuit diagram showing a specific circuit example of the present invention, FIG. 6 is a time chart for explaining the operation of the circuit example of FIG. 5, and FIG. 7 is an example of a conventional telephone circuit. FIG.

Continuing from the front page (73) Patent holder 999999999 Meisei Electric Co., Ltd. 2-57-7 Koishikawa, Bunkyo-ku, Tokyo (72) Inventor Eiji Morikami 1-41-7 Kugayama, Suginami-ku, Tokyo Iwasaki Tsushinki Co., Ltd. Inside the company (72) Inventor Keiichi Koyama 1-41 Kugayama, Suginami-ku, Tokyo Iwasaki Communication Equipment Co., Ltd. (72) Inventor Kenzo Masuoka 1-6-1, Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Inventor Makoto Shimizu Nippon Telegraph and Telephone Corporation, 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo (72) Inventor Kimitoshi Nakamura 1-1-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation ( 72) Inventor Masanori Tanaka 3-1-1 Asahigaoka, Hino-shi, Tokyo Inside the Toshiba Hino Plant (72) Inventor Kazuhiro Izuka 3-1-1 Asahigaoka, Hino-shi, Tokyo Inside the Toshiba Hino Plant (72) Inventor Tetsuya Imahori 2-23-2 Nishigotanda, Shinagawa-ku, Tokyo Kanda Inside Telecommunications Industry Co., Ltd. (72) Michio Shiba 2-23-2 Nishigotanda, Shinagawa-ku, Tokyo Inside Kanda Telecommunications Industry Co., Ltd. (72) Takahisa Arai 2-57 Koishikawa, Bunkyo-ku, Tokyo Inside Electric Co., Ltd. (72) Inventor Kenichi Shiina 2-57, Koishikawa, Bunkyo-ku, Tokyo Meisei Electric Co., Ltd. (56) References JP-A-62-25955 (JP, A) (58) Fields investigated (Int.Cl. ⁶ , DB name) H04M 1/00 H04M 1/72

Claims (1)

(57) [Claims] An incoming call circuit for displaying an incoming call in response to a call signal arriving at a connected line, a call circuit operating by a loop current supplied from the line, a dial for inputting number information, A telephone having a control circuit for controlling the state of each circuit including the dial, a hold circuit for holding a call, and a means for detecting off-hook of another telephone connected in parallel to the line and releasing the hold In the telephone circuit of the first aspect, first means for presetting its own number in the telephone, and a unit code is formed with a repetition frequency outside a predetermined speech frequency band by a number inputted by the dial Second means for generating a pulse train, third means for transmitting the pulse train as a data signal to the line, detecting the data signal on the line, and A fourth means for reproducing the data signal, a fifth means for decoding the data signal, and a sixth means for generating a ringing tone. When the data signal is transmitted by dialing, the decrypted data signal is transmitted to the other telephone connected in parallel to the line with the own number input to the first means in the other telephone. A telephone circuit characterized in that the coincidence drives the receiving circuit and calls the other telephone connected in parallel to the line.