JP3287625B2 - Network controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network control device for switching between a telephone and a facsimile.

[0002]

2. Description of the Related Art A communication unit of a conventional facsimile apparatus is shown in FIG.
As described above, the telephone lines L1 and L2, the NCU unit (network control unit) 71 connected to the lines, the telephone circuit unit 72, and the NC
It comprises a facsimile signal input / output unit 73 connected to the U unit 71.

In this configuration, an NCU unit 71 selects one of a telephone circuit unit 72 and a facsimile signal input / output unit 73 and is connected to lines L1 and L2.

[0004] The NCU unit 71 is mainly composed of a hybrid circuit 74 for converting two lines into four lines, and a facsimile signal input / output unit 73 is connected to the four lines. The telephone circuit section 72 is placed on the two-wire side and is selectively connected by a mechanical contact CML relay 75. In other words, in the call operation, CM
The contact of the L relay 75 is set to the telephone circuit unit 72 side to disconnect the connection between the facsimile signal input / output unit 73 and the line. In the facsimile communication, the contact of the CML relay 75 is switched to the telephone circuit unit 72 side. The line connection has been disconnected.

In order to detect an off-hook during facsimile communication, an off-hook detection circuit 7 using an H relay is provided.
6 is also installed.

The telephone circuit section 72 is a commercially available product, and the description is omitted here.

When a call is made, a dial pulse is generated by turning on an S relay 78 and then turning on / off a P relay 77 in order to secure a make-up rate.

The incoming call is detected by the incoming call detection circuit 79 at 16 Hz.
This is performed by detecting a call signal.

[0009]

However, in the above-mentioned conventional example, the telephone circuit unit 72 is arranged on the two-wire side, and the call and the facsimile communication are switched by the NCU unit 71 to operate. Therefore, there are the following disadvantages. Was.

(1) The configuration of the NCU 71 is complicated,
This is an obstacle to miniaturization and cost reduction of the circuit.

[0011]

(2) In order to generate a dial pulse, an S relay 78 is also required in addition to the P relay 77, and the control is complicated, which is an obstacle to miniaturization and cost reduction.

[0013]

According to the present invention, in a network controller connected to a telephone line for switching between a telephone and a facsimile, a hybrid means for performing both 2-wire / 4-wire conversion and DC loop holding is provided. Facsimile / telephone switching means is provided after four-wire conversion, incoming call detecting means and dial pulse generating means are connected in parallel to a telephone line, and hybrid means, said incoming call detecting means and dial pulse generating means are connected in series. This solves the above-mentioned drawback.

[0014]

[0015]

FIG. 1 is a block diagram showing a configuration of a facsimile apparatus embodying the present invention.
2 is a telephone line (analog), 3 is an NC that connects line 2
U unit (network control unit), 4 is a switching circuit connected to NCU unit 3, 5 is a telephone circuit unit connected to switching circuit 4, 6 is a facsimile signal input / output unit, 7 is a control unit, and 8 is an operation unit. ,
9 is an ISDN (Integrated Services Digital Network) interface, and 10 is an ISDN line.

A handset is connected to the telephone circuit unit 5.

First, the transmitting operation will be described (FIG. 5).

When the handset is picked up for transmission (step S51), the hook on the handset table is
The switch turns off, and the I / O (input / output port) goes to “H”.
Is transmitted to the control unit 7 in the form of an I / O signal as a handset off signal, and an off-hook sound is sent from the sound source of the facsimile signal input / output unit 6 to the handset (step S52).

The control unit 7 checks the use status of the line (used / unused by the facsimile signal input / output unit 6) (step S53). If it is used, the control unit 7 is busy from the sound source of the facsimile signal input / output unit 6. Notify that there is.

If not used, the control section 7 dials the number designated by the operator through the operation section 8 using the P relay 47 (FIG. 4) to form a DC loop of the line (step S5).
4). Thereafter, the switching circuit 4 is set on the speech side to secure a communication path (step S55). Telephone circuit 5
Outputs the voice input from the handset with gain control. The voice input from the line 2 is similarly adjusted to a predetermined gain by the telephone circuit unit 5 and output to the handset (step S56).

The telephone call is held until the hook switch of the handset is turned on and the handset is recognized as being turned on. When the hook switch is turned on (step S57), the line is released (step S58), the switching circuit 4 is set to the facsimile signal input / output unit 6 side (step S59), and the call is completed. The reason for switching to the facsimile input / output unit 6 at the time of termination is to always monitor the incoming call from the facsimile network using the 1300 Hz detection function of the modem.

Next, the receiving operation will be described (FIG. 6).

Incoming call from line detected (CI signal on)
When this is done (step S61), a ring tone is emitted from the sound source of the facsimile signal input / output unit 6 (step S62). Here, in the case of automatic reception, a facsimile communication operation is performed, and in the case of manual reception (step S63), a handset-off signal is waited for (step S64). When the handset is turned off, the control unit 7 controls the NCU unit 3 to capture a line (step S65), and then sets the switching circuit 4 to the speech side (step S66) to secure a communication path (step S66). S67).

Thereafter, as in the transmission operation, the call is held until the handset is turned on (step S68). At the end, the control unit 7 releases the line (step S69) and sets the switching circuit 4 to the FAX side. And complete (Step S7
0).

Next, a circuit configuration of a facsimile apparatus embodying the present invention will be described.

FIG. 2 is a circuit diagram of a main part of a facsimile apparatus embodying the present invention.

The facsimile signal input / output unit 6 includes a modem 22
including. The telephone circuit unit 5 is mainly configured by a control IC (integrated circuit) 21 (for example, HD81020 manufactured by Hitachi). I
C21 has a terminal for input / output with the handset, and performs gain control of an input / output signal with the handset by an internal circuit. Also, I / O signals to and from the handset are
It has a PCM (Pulse Code Modulation) codec for input / output with N lines. Further, the control IC 21 can be connected to the ISDN line 10 via the ISDN interface 9 (for details, refer to the HD81020 catalog).

The above control is programmable, and the volume adjustment between the handset and the line is externally variable. Further, the control IC 21 is not limited to the HD81020, and may be one having a similar function.

The switching circuit 4 is a semiconductor switching circuit 23 using an analog switch (for example, HC4053 manufactured by Hitachi).
including. The IC has three channels for selecting one from two inputs, has a selection signal for each channel, and selects with an I / O signal from the control unit 7.

The switching circuit 4 is not limited to an analog switch, and an operational amplifier or the like may be used to select a signal to be connected by an adding circuit.

In the figure, X, Y, and Z are channel names, one of 0X and 1X is connected to XC, one of 0Y and 1Y is connected to YC, and one of 0Z and 1Z is ZC. Connect to
Any signal is selected by A for X, B for Y, and C for Z (for details, see HC405).
See 3 catalogs).

In this embodiment, ZC, 1X and 1Y are connected to the NCU unit 3. ZC is an output signal to the NCU unit 3, and 1X and 1Y are input signals from the NCU unit 3.

The control IC 21 inputs 0X and 0Z and outputs XC. Also, the modem 22 is 0Y, 1Z
And outputs YC.

Each signal is used as follows.

That is, 0Z is a transmission sound signal (AOUT1) from the handset, 1Z is a G3 transmission signal (G3TX) from the modem, and 0Y is a G3 transmission signal from the modem, 1Y
Is an input signal from the NCU unit 3, 0X is an output signal (AOUT2) obtained by converting a PCMIN signal into an analog signal, 1X is an input signal from the NCU unit 3, ZC is an output signal to the NCU unit 3, and YC is a signal to the modem. The output signal (G3RX) and XC are reception sound signals (AIN) output to the handset via the telephone control IC 21.

The relationship between each channel (X, Y, Z) and the call operation will be described with reference to FIG. However, in FIG. 3, the mark * is Don't care (undefined).

At the time of idling, XC = * (Don't c
are), YC = 1Y, ZC = * (Dout car
The selection signals A, B, and C are set so as to satisfy e). This is because the modem 22 detects an incoming facsimile network from the telephone network as described above.

Next, when talking on the analog telephone network, XC =
1X, YC = 0Y, and ZC = 0Z are set. This is because the output ZC to the NCU unit 3 is connected to AOUT1 (sending sound signal), the input 1X from the NCU unit 3 is connected to AIN (receiving sound signal), and the call signal is connected to the handset. The reason for setting YC = 0Y is to prevent the modem 22 from malfunctioning with a signal from the NCU unit 3.

When talking on ISDN, XC = 0X,
Set so that YC = 1Y and ZC = *. This is a PC
The MIN input signal is decoded inside the telephone control IC ²¹ and output as an analog signal, which is input to the semiconductor switching circuit 23 as 0X from the AOUT2 terminal. Then, the input signal from 0X is returned to AIN, the gain is adjusted inside the IC 21, and then output to the handset. The connection of YC to 1Y is the same as at the time of idling. The transmission signal from the handset is output from PCMOUT after the gain is adjusted by the control IC 21.

In G3 communication, XC = 0X and YC = 1
Set so that Y and ZC = 1Z. This means that the output to the NCU unit 3 is G3TX and the input from the NCU unit 3 is G3R.
X to form a path between the modem 22 and the NCU 3. The reason for setting XC to 0X is to enable simultaneous operation with ISDN communication.

As described above, the telephone call signal from the handset can be directly transmitted as PCM data by the telephone control IC ²¹ via the ISDN. Semiconductor switching circuit 2
3 to switch to G3 communication for talking.

Incidentally, since the ISDN and the telephone network have the same number system, it is not possible to determine the network to be connected only by the input telephone number of the user.

Therefore, a screen selection button is provided on the operation unit 8,
The network to be connected is determined based on the state of the button. In accordance with the determination result, the control unit 7 outputs the selection signals A, B, and C of the semiconductor switching circuit 23 from the I / O port.

With the configuration described above, the NCU unit 3 becomes small as follows. This will be described with reference to FIG.

L1 and L2 are telephone lines, 41 is an audio transformer that also serves as a RET (return) coil, 42
Is an impedance converter composed of an operational amplifier, etc.
1 and 42 constitute a hybrid circuit having both functions of 2-wire / 4-wire conversion and holding of a DC loop. Also, 4
Switches a FAX signal and a TEL signal by a switching circuit and connects the selected signal to the impedance conversion unit 42. An incoming call detection circuit 44 detects a ringing tone (16 Hz) using a photocoupler or the like and notifies the control unit 7 of it. Reference numeral 45 denotes a Zener diode for preventing a malfunction of a signal having a low voltage (27 V (volt) or less in this embodiment) from being erroneously detected as an incoming signal. A varistor 46 is connected in parallel with the resistor R2. In this embodiment, a signal of 2 V or less passes through R2, and the other signals pass through a varistor, so that a ringing tone (13
00 Hz). Reference numeral 47 denotes a P relay for generating a dial pulse, which is used in parallel with the resistor R1 and the capacitor C1 to shape the waveform and secure a make-up rate. The capacitor C2 secures a DC impedance at the time of on-hook and an impedance for a ringing tone (16 Hz).

The relationship between various operations and the blocks used in this embodiment will be described.

First, the incoming call operation will be described.

In the incoming call operation, there is no need to generate a dial pulse, so the P relay 47 is off. Therefore, the ringing tone (16 Hz) from the telephone line passes through the audio transformer 41, the voltage section of 2V or more passes through the varistor 46, and the voltage section of 27V or more passes through the incoming call detection circuit 4.
4, passes through the Zener diode 45 and the capacitor C2 and is connected to the line via the resistor R1. In this state, the detection of the incoming call is notified to the control unit 7 as CI by the current flowing through the incoming call detection circuit 44. Upon receiving this notification, the control unit 7
When the relay 47 is turned on, a DC loop is formed.

This receiving operation is the same for both facsimile and telephone irrespective of the terminal type of the other party.

Next, the calling operation will be described.

In order to generate a dial pulse, the control section 7 controls the P relay 47 on / off. The dial pulse signal is waveform-shaped by R1, C1 and varistor 46, and a waveform satisfying the make ratio is output to the line. In this embodiment, R1 = 220 ohms and C1 = 0.33 μF (microfarad).

During communication, the P relay 47 is on.

[0053]

As described above, the telephone circuit is provided on the 4-wire side of the hybrid circuit, and the telephone and the facsimile are switched and used here. (1) The CML relay and the H relay of the NCU are used. No longer needed. (2) The NCU is small and inexpensive.

[0054]

A RET coil for holding a DC loop;
In addition, a relay for shaping the dial pulse waveform is not required.

[0056]

[0057]

[Brief description of the drawings]

FIG. 1 is a block diagram of a facsimile apparatus embodying the present invention.

FIG. 2 is a detailed diagram of a telephone circuit and a switching circuit embodying the present invention.

FIG. 3 is a diagram showing signals and operation states of a switching circuit embodying the present invention.

FIG. 4 is an NCU circuit diagram embodying the present invention.

FIG. 5 is an operation flowchart of a transmission operation of the facsimile apparatus embodying the present invention.

FIG. 6 is an operation flowchart of reception of a facsimile apparatus embodying the present invention;

FIG. 7 is a diagram showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Facsimile apparatus 2 Telephone line 3 NCU part 4 Switching circuit 5 Telephone circuit 6 Facsimile signal input / output part 21 Telephone control IC 22 Modem 23 Semiconductor switching circuit 41 Audio transformer 42 Impedance conversion part 44 Incoming detection circuit 45 Zener diode 46 Varistor

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-124467 (JP, A) JP-A-2-186866 (JP, A) JP-A-63-198465 (JP, A) JP-A-4- 196664 (JP, A) Japanese Utility Model Hei 1-81061 (JP, U) Japanese Utility Model Hei 2-150891 (JP, U) Japanese Utility Model Utility Model 4-48761 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) H04M 11/00-11/10 H04M 1/00 H04N 1/00 H04N 1/32

Claims (2)

(57) [Claims] 1. A network control device connected to a telephone line for switching between a telephone and a facsimile, comprising hybrid means for performing both 2-wire / 4-wire conversion and DC loop holding, wherein the facsimile / telephone switching means is provided. A network control device provided after four-wire conversion, wherein incoming call detecting means and dial pulse generating means are connected in parallel to a telephone line, and hybrid means, said incoming call detecting means and dial pulse generating means are connected in series. 2. An incoming call detecting means according to claim 1, wherein said incoming call detecting means comprises a DC cut capacitor, a noise cutting Zener diode, a photocoupler, a facsimile network varistor, and a resistor. A network control device comprising a resistor and a capacitor, and wherein the hybrid means comprises an audio transformer also serving as a return coil for holding a DC loop.