JPS61212955A - Telephone set incorpoating modulator and demodulator - Google Patents

Abstract

PURPOSE:To decrease the power conumption current by providing a power changeover circuit connecting selectively the power supply of a MODEM in response to the operation of a switch selecting a communication state. CONSTITUTION:In operating a communication switch DCS 17, a control circuit CNT 16 is activated and data communication state is set. Further, switch circuits CHC12A, 12B are energized in response to the operation of a communication speed selection switch SS 15 and either of MODEMs 11A, 11B is selected. The commercial power supply AC is rectified and stabilized by a power supply section PSR 23 and applied to each section as a local power supply E and applied selectively to the MODEMs 11A, 11B in response to the SS 15 via a power switching circuit PCH 24.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a telephone with a built-in modulator/demodulator.

[Conventional technology]

In recent years, telephone devices have been developed that incorporate a modem (hereinafter referred to as "MODEM") into the telephone and integrate call and data communication functions. It is easy to operate and allows data communication via telephone lines.

However, if multiple MODEMs with different communication states are built in due to differences in communication speed or signal format, etc., always supply power to each MODEM to keep it in operation and select their input/output. It is common to use

In addition, the amplifier for transmitting and receiving the transmission signal is MO
Signals are amplified using the reference voltage generated from the DEM as a reference, but since the reference voltage differs depending on the MODEM, each of these amplifiers is provided for each MODEM.

[Problem that the invention seeks to solve]

However, if power is always supplied to each MODEM, the required power supply current will be too large, making it impossible to use a small and inexpensive power adapter, etc., and if a transmitting and receiving amplifier is provided for each MODEM, the configuration This results in economically unfavorable problems, such as the process becoming complicated and expensive.

[Ω means to solve the problem]

In order to solve the above-mentioned problem, the present invention is constructed by the following means.

That is, in a telephone equipped with a plurality of MODEMs having different communication states, a power supply switching circuit selectively connects the power supply of the MODEM according to the operation of a switch for selecting the communication state;
A switching circuit that selects the input/output of the switch, and a reference voltage of the transmitting amplifier and the receiving amplifier according to the operation of the switch.
It is equipped with a voltage switching circuit selected in correspondence with M.

[Effect]

Therefore, depending on the switch operation, the selected MOD
Power is supplied only to the EM, and a reference voltage corresponding to this MODEM is applied to the transmitting and receiving amplifiers, and the input and output of the MODEM are simultaneously selected.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to figures showing examples.

FIG. 2 is an overall block diagram of the line terminal Ll.

Hook switch I (S'
and relay contact rt1', diode bridge DB
1 and a switch circuit for dial pulse transmission (
An integrated communication circuit (hereinafter referred to as TKC) 2 is connected in series through Sdi 1, which includes:
Transmitting manual terminal (hereinafter referred to as TI) 201, receiving output terminal (hereinafter referred to as Ro") 202, receiving amplifier input terminal (hereinafter referred to as RA)
i) 203, and the receiver amplifier output terminal (hereinafter referred to as
RAo) 204 is provided, and Ro 202 and RAi 203 are connected by contact rt2', and the receiver R is connected between RAo 204 and the positive terminal (hereinafter referred to as Vc) 205 of TKC2. A self-generating transmitter T such as a dynamic type or a capacitor type is connected to a common side terminal (hereinafter referred to as COM) 206 of Ti 202 and TKC2 via a contact S, a contact R 722, and a switch circuit (hereinafter referred to as 5W) 3. The output of the transmitter T is applied between Ti2 and COM2O6, amplified by the internal transmitter amplifier, and then connected between Vc 202 and COM 206. On the other hand, the received audio signal applied between Vc 205 and COM 206 is subjected to sidetone prevention and is transmitted to Ro.
The signal appears at 202, is amplified by the receiver amplifier between RAi 203 and RAo 204, and is sent between RAo 204 and Vc 205 to drive the receiver R.

Note that each amplifier in the TKCZ operates using loop current from the telephone line as a power source.

゛Also, on the output side of the diode bridge DB.

This is also an integrated dial circuit (hereinafter referred to as DIC) that operates using part of the loop current as a power source. 4 is a sat
Sdi 1 is controlled via the drive circuit (DRV) IA in response to the operation of a dial key (hereinafter referred to as DIR) 5, which is connected in parallel to i and TKC2 and has double contacts, and turns off and on. In addition to sending dial pulses, pIC4 has a redial function,
In accordance with the operation of the redial key 6, Sdi 1 is controlled again based on the memorized number dialed immediately before, and a redial call is made.

However, SW7 is inserted between DIC4 and DIK"5, and while the commercial power supply used as the main power supply is energized,
#) DIC4 is controlled by the operation of pSW7 as described below.

A tone ringer (hereinafter referred to as TRG) 9 is bridge-connected to the contact point rZ11 side of the hook switch H8' via a ringing signal detection circuit (hereinafter referred to as RDT) 8. Since the TRG 9 drives the speaker sp, the incoming call is notified by this.

On the other hand, for example 1200 bit/l1iec and 300
MODEM with different communication speed from bit/9e[f
11A and 11B are provided, and switching circuits (hereinafter referred to as CHC) 12A and 12B are interposed on both sides of these, and data terminal equipment (hereinafter referred to as DTE) 14 is connected via a CHCl2A interface (hereinafter referred to as I/F). is connected to the communication speed selection switch (hereinafter referred to as 5s) 15
CHCi2A upon manipulation of.

12B responds and selects either MODEM IIA or MODEM IIB.

In addition, processors such as microprocessors (hereinafter referred to as CP)
U ) and a control circuit (hereinafter referred to as CNT) consisting of memory, etc.
) 16 is provided to control SW7 according to the operation of DIK5 and redial key 6 to make a dial call, while MODEM 11A is controlled by the output of 5S15.
, determines the selection status of 11B and also switches the communication switch (
Hereinafter, when DC8) 17 is operated, CNT16 will respond and set the data communication status.
In order to control B to allow the data signal to pass, and at the same time drive relays RLI, RL2 and SW7,
Contacts rt21 + rt2'' connect the transmission output D8 and reception input DR of CHC12B to Ti201 and Ro 202 of TKC2 through matching transformers T1+T2, respectively, and by the operation of contact rt1', Regardless of the status of hook switch H8I, it connects line terminal Ll and TKO2 to close the DC loop, disables the operation of DIK 5 and redial key 6, and prevents dialing from interfering with data communication. to prevent this from happening.

Therefore, dialing off-hook or
After going off-hook in response to an incoming call, use the transmitter T and receiver R to talk to the other party, and for data communication, operate the DC817 to enter the data communication state. ) signals and other transmitted data signals are
A similar received data signal is transmitted from the transmit output DB of CHCl2B to the telephone line via TKC2, and a similar received data signal is transmitted from the telephone line to the receive input D of CHCl2B via TKC2.
This signal is applied to R, thereby allowing the DTE 14 to transmit and receive data signals.

Also, if you do not go off-hook in response to an incoming call,
In response to the RDT 8 detecting the arrival of a calling signal, the CNT 16 responds based on its detection output, and the I/F 13
Since the carrier detection (hereinafter referred to as CI) signal is sent to the DTE 14 via the carrier detection signal (hereinafter referred to as CI), if the DTE 14 sends out a ready completion (hereinafter referred to as ER) signal in accordance with this, the CNT 16 sets the data communication state. Communication is automatically received.

Note that during automatic reception, the CNT 16 stops controlling the SW 7, so even if the DIK 5 is still operated and the dial key 6 is operated, the DIC 4 does not respond and dialing is not performed.

In addition, the DIC4 is equipped with a dialing function using not only pulse dialing but also composite voice frequency (hereinafter referred to as MF) signals.
and the MF multiplied signal MF” are selected, and the MF
When double signal is selected, DIC
4 drives SW3 with the mute signal MUTE, and 'l'Kc 2 is output via the correction circuit (hereinafter referred to as REV) 4A.
After connecting the MF double signal output to Ti 201, REV
After setting the signal level and reducing harmonic components at 4A, a signal is transmitted via TKC2.

In addition, a hold key is provided in KB18, and a hold circuit (not shown in the diagram) is provided, and in response to the operation of the hold key, the hold circuit maintains the DC loop closed regardless of the state of the hook switch H8''. At the same time, relay RL3 is driven to contact rt3' to generate a hold tone generation circuit (hereinafter referred to as H).
Connect TG ) 19 to Ti201 of TKC2, and connect HT
The hold tone such as the melody generated by G19 is sent to the TKC2 kana telephone line.

On the other hand, a partner response detection circuit (hereinafter referred to as ASD) for detecting polarity reversal of the loop current is installed between contact rt1' and hook switch H8' and on the diode bridge DB side.
21 is inserted and MODEMllA or 11 selected by 5S15 via CHCl2B.
A watchdog circuit (hereinafter referred to as WNC) 22 to which clock pulses and data signals from B is provided, monitors the operating status of MODEM 11A or 11B, and detects each detection output of ASD21 and WDC22. is given to CNT16, and these are given CNT
16 will respond.

Furthermore, the MODEM 11A has a first mode and a second mode depending on the frequency of the carrier wave used, and the situations thereof are as shown in the following table.

Therefore, mode selection (hereinafter referred to as MS) from CNT16
) Mode 1 or 2 is set depending on the signal, and transmission is performed at the frequency of the screen, and signals are received at the opposite frequency to the set mode.

However, the mode can be set manually or automatically, and in KB18 [Mode IJ
, r2J and "mode 'auto" keys are provided individually. [Mode IJ and r2J keys are used to manually set the mode, and the "mode auto" key is used to set the mode automatically. .

The KB18 is equipped with a "speaker key" for the on-7 monitor circuit, which is omitted from the diagram. Operating this key closes the DC loop, making it possible to monitor using the amplifier and speaker, and also activates the relay. The key to select the connection status on the MODEM side driven by RL1 and 2 is also in KB.
18, and "manual connection IJ, r2j and"
In "Automatic connection", each relay is automatically driven according to the outgoing or incoming operation, and in "Manual connection", the relay RLI is driven by the operation of the speaker key. Furthermore, relay RL2 is driven in response to the operation of DC817.

However, in the case of "manual connection 1", the drive of the relay is stopped in response to the stop of the ER multiplier signal, and in the case of "-manual connection 2", the drive of the relay is stopped in response to the reset of the DC 817.

In addition, commercial power AC is rectified and stabilized by a power supply unit (hereinafter referred to as PSR) 23 and then supplied to each part as local power supply E. However, for MODEMs 11A and 11B, a power supply switching circuit (hereinafter referred to as , PCH) 24,
It is said that it is selectively supplied according to the operation of 5S15.

Figure 1 shows MODEM IIA, 11B, CH
The main circuit diagram includes C12B, 8815, and PCH24. The received data signal applied to the receiving input DR is amplified by a receiving amplifier including resistors R1 to R3 and a differential amplifier A, and is converted into an analog signal. 5W4 for switches etc.
1 or 42, MODEM 11A, 11B is converted into an actual circuit through a level adjustment circuit using resistors R1or R21 and variable resistors RVI IRVs.
These analog outputs AO are applied to the resistors R1t + R12p R22
z 5W4 similar to 5W41.42 through a level adjustment circuit with R23 and variable resistor RV2 + RV4
3 or 44, differential amplifier A2 + resistor R5~R
7, and is amplified by a transmission amplifier with a capacitor C13 and sent out as a transmission data signal from a transmission output D8, but each amplifier is a 5W45 signal similar to 5W41.42.
Voltage switching circuit (hereinafter referred to as 5GC) consisting of ~48 49A
, 49B, amplification is performed based on the voltage sent from the reference voltage output SG of MODEM 11A, IIB, and 5W41 to 48 are 5S1
MODEM IIA given according to the operation of 5.

Since it is turned off according to the voltage from the analog common potential output AC of 11B, if 8815 is on the (1200) side, 5W42.5W43 and SGC49A.

SW46 and SW47 of 49H are on, MODE
The analog human power AIN O and the same output AO of MllA are selected, the reference voltage output SG is selected, and P
5 of switching transistors etc. that constitute CH24
w5o is on, PSR23 to MODEM 11A
The local power source E is supplied from the source, and the device enters the operating state.

On the other hand, if 5sis is on the (300) side, 5W4
1.5W44. and SGC49A, 49B 5
When W45.8W48 is on, the analog manual input AIN of MODEM 11B and its output AO are selected, and the reference voltage output SG is selected, and when 5w5i, which is similar to 5w5o of PHC24, is on, MODEM
Local power supply E is supplied to 11B and it becomes operational.

In addition, a clock pulse switching circuit (hereinafter referred to as CLC) 59 is configured by an inverter (hereinafter referred to as IN) 55, an AND gate) 56, 57, and an OR gate 58.
, if SS 15 is set to the (1200) side, the other contact of this will be open, and the pull-up resistor R70 will open the other contact.
Local power E from PSR23 is applied and CLo 59
In order to set the IN550 input to "H" (high level), the MO gate 57 is turned on and MODEM 11A
The clock pulse from the clock pulse output CLK of A
wDc2 via ND gate 57 and OR gate 58
At the same time, the output of the IN 55 becomes "L" (low level), and the gate 56 of the IN 55 is turned off.

For the above, if 5sis is on the (300) side, lN5
The input of 5 becomes ``L'', the output of this changes to ``H'', and the AND gate 56 is turned on.
A clock pulse from the clock pulse output CLK of B is similarly sent out through AND gate 56 and OR gate 58, and AND gate 51 is turned off.

Therefore, depending on the operation of SS 15 MODEMll
The power supplies of A and IIB are selectively connected to reduce power consumption current, and the transmitting amplifier and receiving amplifier are shared, simplifying the configuration.

At the same time, the clock pulse for WDC22 is also CLC5.
9, so it does not interfere with the monitoring operation.

However, the reference voltage is MODEM 11A, IIB
Separately generated depending on the 5W4
1 to 5W48, SW50, and SW51 may be replaced with similar switching elements, and CLC59 may be replaced with other equivalent circuits.

Also, the communication status of MODEM 11A and 11B is as follows.
Not only the communication speed but also the signal format such as the modulation method may be different, and if necessary, a predetermined number of desired ones may be provided, and the configuration of each circuit may be determined accordingly, and the present invention can be freely modified in various ways. be.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, power consumption current is reduced, it becomes possible to use a small capacity and inexpensive power supply section, and multiple configurations are simplified by sharing each amplifier. Remarkable effects can be obtained in various telephones incorporating MODEM.

[Brief explanation of drawings]

The figures show an embodiment of the present invention, with FIG. 1 being a circuit diagram of the main part, and FIG. 2 being an overall block diagram. 11A, 11B...MODEM (modulator/demodulator),
12A. 12B...CHC (switching circuit), 15...SS
(communication speed selection switch), 16...CNT (control circuit), 24...PCH (power supply switching circuit), 41~
48, 50, 51...SW (switch circuit), 49
A, 49B...SGC (voltage switching circuit), Al
+ A2... Differential amplifier, R1"R3+ R5-R
7...Resistor, C10...Capacitor, DR...
...Reception input, D8...Transmission output.

Claims (1)

[Claims] In a telephone equipped with a plurality of built-in modems having mutually different communication states, a power supply switching circuit selectively connects a power source of the modem according to the operation of a switch for selecting a communication state; A modulation/demodulation device comprising: a switching circuit that selects input/output of the modulation/demodulator; and a voltage switching circuit that selects reference voltages of a transmitting amplifier and a receiving amplifier in accordance with the operation of the switch. Built-in telephone.