JPH10136119A - Communication terminal equipment changeover controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent other communication terminal equipment (facsimile equipment) from giving any adverse effect onto a line by connecting the line to a specific terminal equipment (telephone set) in the specific terminal equipment communication mode so as to disconnect the line from the other communication terminal equipment (facsimile equipment) thereby preventing reduction in the line impedance. SOLUTION: A bypass switch SR 3, a changeover switch CML 4, an impedance changeover switch DP 5 and an amplification factor changeover switch PP 6 are provided in a line between a specific communication terminal equipment T1 and other communication terminal equipment T2. A signal control section 8 receives an output of a call signal detector R 17 to switch the switches SR 3, CML 4, DP 5 and PP 6 to set any of the specific terminal equipment communication mode, the other terminal equipment communication mode and the specific number detection mode for states of each switch. Thus, the reduction in the impedance of the communication line is prevented in the specific terminal equipment communication mode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication terminal switching control device for efficiently and accurately switching a plurality of communication terminals such as a facsimile and a telephone when the terminals are connected to a communication line.

[0002]

2. Description of the Related Art Facsimile is widely used not only for business use but also for general household use. Such a facsimile terminal uses the same telephone line to make a call, so that the telephone terminals are usually connected simultaneously. In this case, a telephone integrated with the facsimile terminal may be used, or a telephone terminal external to the facsimile terminal may be used. In such a case, for example, when a facsimile is received, a tone for facsimile connection is heard when the telephone terminal is picked up. At this time, before the handset is lowered, a key specified in advance is pressed to notify the switching to the facsimile terminal, and then the handset is lowered. Conventionally, switching between a telephone terminal and a facsimile terminal has generally been performed in such a procedure. Almost the same control operation is performed when a computer and other communication terminals are simultaneously connected to a general communication line.

[0003]

In the communication terminal switching control apparatus as described above, when a plurality of communication terminals are connected to the same communication line, the line impedance generally decreases, and the transmission at the communication terminal is reduced. This can have a negative effect on the communication line itself, as well as a decrease in quality. For example, considering the case where a telephone and a facsimile are connected to the same line as described above, a high impedance is desirable to avoid affecting the line impedance during a specific terminal communication mode of the facsimile, but during operation, in order to match the line impedance, In addition, there is a dilemma that it is desirable to reduce the impedance in order to improve transmission quality.

As a technique for switching communication terminals as described above, a capacitor and a protection resistor for cutting line DC current are inserted into the primary side of a facsimile line transformer.
During facsimile mode (during communication), there is introduced a technique of using a relay to disconnect them (Japanese Patent Publication No.
No. 12188). However, in this method, since an AC loop is always generated even during standby, connecting a plurality of communication terminals to the same communication line results in a decrease in line impedance, and in addition to a reduction in transmission quality at the communication terminal,
It may also affect the communication line itself. Also,
Since the special number test can always be performed, when dialing from another terminal, if the number matches the special number, the terminal operates and captures the line.

To increase the line impedance, it is necessary to increase the insertion resistance. However, if the insertion resistance is large, when a special number signal or the like specifying the facsimile flows during the telephone mode, the voltage drop at the resistance becomes large,
It may affect the signal detection ability on the secondary side of the input transformer and cause a malfunction. At the same time, impedance matching between the communication line and the facsimile in the facsimile mode sometimes becomes difficult. Further, since the mode switching is performed by the user, it may cause an operation error and may be a cause of annoyance.

[0006]

The present invention employs the following structure to solve the above problems. <Structure 1> A communication terminal switching control device of the present invention includes a changeover switch for selectively connecting one of a specific communication terminal and another communication terminal to a communication line, and bypassing the changeover switch. A bypass switch for directly connecting a communication line and a specific communication terminal, a switch for switching an impedance between the communication line and the other communication terminal, a switch for switching an input signal amplification factor to the other communication terminal, A paging signal detector for detecting a paging signal by connecting; a special number signal detector for detecting a special number signal for specifying the other communication terminal; and a switch for each switch according to the output of the paging signal detector and the special number signal detector. And a signal control unit for controlling the switching, the signal control unit,
When the specific communication terminal starts communication, the bypass switch to the specific communication terminal, the changeover switch to the other communication terminal, the impedance changeover switch to the high impedance side, the amplification rate changeover switch A special number test mode for connecting to the high amplification rate side and enabling a call for the specific communication terminal; and when the other communication terminal starts communication, connect the changeover switch to the other communication terminal and connect the bypass switch. Off, set the impedance changeover switch to the low impedance side,
Another terminal communication mode in which the amplification rate changeover switch is set to the low amplification rate side to enable communication of another terminal device alone,
A communication terminal switching control device for controlling switching to a specific terminal communication mode in which the switch is connected to the specific communication terminal and the bypass switch is connected to the specific communication terminal.

<Structure 2> In the structure 1, the amplification rate changeover switch is connected to the high amplification rate side, and at the same time, the secondary side of the line transformer between the communication line and the other communication terminal is set to high impedance. A communication terminal switching control device, characterized in that:

<Configuration 3> A specific communication terminal and another communication terminal are both connected in parallel to a communication line, and a switch for switching impedance between the communication line and the another communication terminal is provided.
A switch for switching an input signal amplifier to the other communication terminal, a call signal detector connected to a line to detect a call signal, and a special signal signal detector for detecting a special signal signal identifying the other communication terminal, A signal control unit that controls the switching of each switch according to the output of the call signal detector and the special number signal detector. The signal control unit is configured to perform the impedance changeover switch when the specific communication terminal starts communication. On the high impedance side, the gain switching switch is connected to the high gain side, and a special number test mode that enables the special number signal of the specific communication terminal to be tested,
When the other communication terminal starts communication, another terminal communication mode in which the impedance changeover switch is set to the low impedance side and the amplification rate changeover switch is set to the low amplification side to enable communication of another terminal device alone. A communication terminal switching control device for controlling switching between the communication terminal and the communication terminal.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to specific examples. FIG. 1 is a connection diagram showing a main part of the device of the present invention. The present invention is implemented by, for example, a functional block having a configuration as shown in FIG. The communication line 1 is connected to a communication terminal T1 and another communication terminal T2. Then, these communication terminals T1, T
Between the communication line 2 and the communication line 1, a bypass switch SR3, a changeover switch CML4, an impedance changeover switch DP5, and an amplification factor changeover switch PP6 are provided. The bypass switch SR3 is a switch for performing an operation of directly connecting or disconnecting the communication line 1 and the communication terminal T1. When the switch is on (ON), the two are directly connected, and when the switch is off (OFF), both are connected. Is disconnected. The changeover switch CML4 is a switch that can be switched to select either a state in which the communication line 1 is connected to the communication terminal T1 or a state in which the communication line 1 is connected to another communication terminal T2. The impedance changeover switch DP5 is a switch for changing the impedance between the communication line 1 and another communication terminal T2. The amplification rate changeover switch PP6 is an input signal amplification degree conversion switch from the line to the communication terminal T2.

A call signal detector RI7 is inserted in a line connecting the communication terminal T1 and the communication line 1. The paging signal detector 7 is configured to detect a paging signal of the communication terminal T1 and transmit this to the signal control unit 8. The signal control unit 8 is a call signal detector 7
Switch SR3, changeover switch CML4, impedance changeover switch D
P5 and a signal control unit 8 for controlling the operation of the amplifier changeover switch PP6. In the present invention, the signal control unit 8 performs three modes of the specific terminal communication mode shown in FIG. 1A, another terminal communication mode shown in FIG. 2B, and the special number verification mode shown in FIG. Each switch is controlled to be in one of several modes. The control result is transmitted from the signal control unit 8 to another communication terminal T2 as necessary.

In the specific terminal communication mode (a), the communication line 1 and the communication terminal T1 are turned off by the bypass switch SR3, the impedance changeover switch DP5 is connected to the high impedance side, and the gain changeover switch PP6 is connected to the low gain side. The changeover switch CML4 is the communication line 1
And the communication terminal T1. In the other terminal communication mode (b), the bypass switch SR3 is turned off, the impedance changeover switch DP5 is set to the low impedance side, and the gain changeover switch PP6 is set to the low gain side, so that the communication terminal T1 is disconnected from the communication line 1. The changeover switch CML4 connects the communication terminal T2 to the communication line 1. In the special number verification mode (c), the bypass switch SR3 is turned on, the communication line 1 is connected to the communication terminal T1, the changeover switch CML4 is connected between the communication line 1 and the communication terminal T2, and the impedance changeover switch DP5 is set to the high impedance. The amplification factor changeover switch PP6 is connected to the high amplification factor side.

A call signal detector RI7 is connected to the communication line 1 and detects a call signal. Signal control unit 8
Has a CPU (Central Processing Unit) inside, and based on the output from the call signal detector 7, the bypass switch SR3, the changeover switch CML4, the impedance changeover switch DP5, and the amplification rate changeover switch PP6
Switch.

Next, the operation of the present invention will be described with reference to FIGS. To facilitate understanding of the description, it is assumed that the communication line is a telephone line, the communication terminal T1 is a telephone, and the communication terminal T2 is a facsimile. In the specific terminal communication mode (a), the changeover switch CML4 is set to the telephone side, and the bypass switch S
R3 is turned off and connected to the telephone, and either impedance switch DP5 or amplification factor switch PP6 may be used. Since the facsimile terminal is disconnected by waiting in the above state, there is no danger of lowering the line impedance. Next, when a calling signal flows through the line, the signal is detected by the calling signal detector 7 and based on the output, the signal control unit 8 sets the changeover switch CML4 to the facsimile side and sets the amplification rate changeover switch PP6 to the high level. The bypass switch SR3 is connected to the telephone on the amplification side, and the mode shifts to the special number verification mode (c).

In this telephone mode, the communication terminal T1 and another communication terminal T2 are connected in parallel to the communication line 1. However, the input impedance to the facsimile viewed from the communication line is such that the impedance changeover switch DP5 is set to the high impedance side. Because it is connected (usually about 30KΩ)
A reduction in line impedance can be avoided. In this state, the special number signal flowing from the communication line 1 or the communication terminal T1 is transmitted to the high-impedance side of the changeover switch CML4 and the impedance changeover switch DP5 and to the facsimile through the high-amplitude side of the amplification-factor changeover switch PP6. At this time, since the signal attenuation due to the high impedance is compensated by switching the amplification factor to the high amplification factor, a decrease in sensitivity can be avoided.

Next, the facsimile which has received the special number signal transmits an answer signal to the signal control section 8 after confirming that this signal is a special number internally. Upon receiving the answer signal, the signal control unit 8 sets the impedance changeover switch DP5 to the low impedance side, sets the gain changeover switch PP6 to the low gain side, turns off the bypass switch SR3, and shifts to another terminal communication mode (b).

In this mode, the impedance between the communication line 1 and the facsimile terminal 10 matches the impedance of the communication line (normal line impedance is 600
Ω). Since the telephone is disconnected from the line and the amplification factor changeover switch has switched from the high amplification factor to the low amplification factor in the above (c), unnecessary noise and the like are not picked up.

<Specific Circuit Configuration> Hereinafter, a specific circuit configuration of the device of the present invention will be described. FIG. 3 shows a connection diagram of the device of the present invention. This example corresponds to the communication terminal T1 described above.
, A telephone terminal 9A is added in parallel with the telephone terminal 9, and a facsimile terminal 10 is used as a communication terminal T2. The communication line 1 is a general telephone public line. The facsimile terminal 10 is thus connected to the communication line 1. As shown in FIG. 1, an internal circuit of a facsimile terminal and a telephone terminal 9 are connected to the communication line 1 in parallel. Here, the internal circuit 11 of the facsimile terminal means a modulator and tone transmitter 13 and a demodulator and tone detector 12 inside the facsimile.

A changeover switch CML4 is provided to connect the communication line 1 to the internal circuit of the facsimile terminal 10. When the changeover switch CML4 is switched, the communication line 1 and the facsimile terminal side of the facsimile terminal 10 are connected. A bypass switch SR3 is provided to bypass the changeover switch CML4. When this is on, the communication line 1 and the telephone terminal 9 are connected regardless of the connection of the changeover switch CML4. Further, an impedance changeover switch DP5 and an amplification factor changeover switch P for switching the impedance between the communication line 1 and the facsimile.
P6 is provided. Here, the impedance changeover switch DP5 intermittently interrupts the DC loop to generate a dial pulse. However, this operation is performed only when the transformer T17 can supply a DC current.

FIG. 6 shows another specific circuit example (part 2) of the device of the present invention. When a direct current cannot be supplied, as shown in FIG. 6, the direct current path to the transformer T17 is cut off by C0, and the switch DP is turned on to connect the direct current circuit DC. In this case, the impedance changeover switch DP5 is divided into MUTE having a function of switching impedance and DP having a function of generating a DP waveform.

The facsimile terminal 10 demodulates a facsimile reception signal and detects a tone, a demodulator and tone detector 12, a facsimile transmission signal and a tone, a modulator and a tone transmission. , An amplifier 15 for amplifying a transmission signal, an amplifier 16 for amplifying a reception signal, a paging signal detector 7 connected to a line for detecting a paging signal, and controlling each switch using the paging signal. A signal control unit 8, a relay driving unit 14, and a transformer 17 for DC-insulating and separating the line and the facsimile are provided. Next, the operation of the specific example will be described in detail with reference to the timing chart shown in FIG.

In the following description of the operation, the numbers in parentheses indicate the timing shown in FIG.
The same shall apply. When a telephone call signal flows from the communication line 1, the bell of the telephone terminal 9 rings (1), and at the same time, the call signal detector RI7 detects the call signal (2). At this time, the bypass switch SR3 and the changeover switch CML4 are connected to the telephone, the impedance changeover switch DP5 is connected to the high impedance side, and the gain changeover switch PP6 is connected to the low gain side (3) (the specific terminal communication mode). (A)). The output of the call signal detector RI7 is guided to a signal control unit (CPU) 8, which generates a relay control signal, passes through a relay drive unit 14, sets the changeover switch CML4 to the facsimile side, and sets the amplification ratio changeover switch PP6 to high amplification. Switch to the rate side. Here, R2 and R are set by closing the switch.
4 are arranged in parallel, and the amplification ratio can be increased by changing the impedance ratio with R3. At this point, the mode changes to the special number test mode (c).

At this time, since the impedance changeover switch DP5 is open until a line supplement request (a special number is transmitted), the calling signal is represented by a resistor R, a capacitor C,
Although the current flows through the transformer 17, the current of the call signal is very small and does not affect the line requirements because the value of the resistor R is large. Changeover switch CML
At the same time as 4, the amplification factor changeover switch PP6 is also closed, so that the amplification factor increases, thereby compensating for the attenuation of the line signal determined by the ratio of the resistance R and the capacitor C and the additional impedance of the transformer 17. Next, when you hear the facsimile transmission signal when you pick up the phone, or when you want to put the facsimile in the receiving state at the request of the other party during a call,
A special number signal (tone signal) is transmitted by a push button (a button previously determined as a special number) of the telephone (4).

The special number signal passes through the communication line 1, the changeover switch CML4, passes through a resistor R and a capacitor C, passes through a transformer, is amplified by an amplifier AMP15, and is input to a demodulator and a tone detector 12. The tone detector detects that it is a special number and notifies the signal control unit 8. The signal control section 8 drives the relay drive section 14 to close the impedance changeover switch DP5, opens the amplification rate changeover switch PP6 (5), sends an answer signal to the line, and opens the bypass switch SR3 (6). Further, the telephone confirms the answer signal and turns ON-FOOK (7). This state is the other terminal communication mode (b), and the communication line 1 is connected to the facsimile.

<Other Circuit Examples> FIG. 5 shows another specific circuit example (part 1) of the apparatus of the present invention. In a specific example,
The amplification factor changeover switch PP6 is replaced with a two-contact switch, and one of its contacts is connected to the terminating resistor R1 of the transformer T17.
And the other is selectively connected to a resistor R4 for switching the amplification factor. By doing so, when the amplifier changeover switch PP6 is connected to the high amplification rate side (R4 side in FIG. 5), the secondary impedance of the transformer T17 is high, and the amplification rate is further increased as compared with the above specific example. Therefore, the impedance of the resistor R and the capacitor C can be set higher, and the degree of influence on the line can be reduced. Other configurations and operations are the same as those in the above specific example.

[0025]

As described above, according to the first embodiment, in the specific terminal communication mode, the changeover switch CML4,
Since the bypass switch SR3 is also connected to the specific communication terminal (telephone) and is disconnected from other communication terminals (facsimile), the facsimile has no adverse effect on the line, not to mention lowering the line impedance. Absent. In the specific communication terminal mode, a specific communication terminal (telephone) and another communication terminal (facsimile) are connected in parallel to the line, but since a high impedance is connected between the line and the other communication terminal, the line impedance is reduced. Drops can be avoided. When the special number signal flows in this state, the amplification factor change-over switch PP6 operates at the same time to compensate for the signal attenuation at the high impedance, so that the detection sensitivity of the special number signal can be prevented from lowering. Further, since the switching of each switch is performed by a signal control unit having a CPU therein, it can be performed accurately and efficiently, and remote switching can be performed from a remote place. Further, the same operation can be performed from another telephone 9A connected in parallel to another communication terminal (facsimile).

[Brief description of the drawings]

FIG. 1 is an example (part 1) of a main circuit of a device of the present invention.

FIG. 2 is an example (part 2) of a main circuit of the device of the present invention.

FIG. 3 is a specific circuit example of the device of the present invention.

FIG. 4 is a timing chart of a specific circuit example of the device of the present invention.

FIG. 5 is another specific circuit example (part 1) of the device of the present invention.

FIG. 6 is another specific circuit example (part 2) of the device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Communication line 3 Bypass switch 4 Changeover switch 5 Impedance changeover switch 6 Amplification rate changeover switch 7 Call signal detector 8 Signal control unit T1, T2 Communication terminal

Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04N 1/32 H04N 1/32 Z

Claims (3)

[Claims] 1. A changeover switch for selectively connecting one of a specific communication terminal and another communication terminal to a communication line, and bypassing the changeover switch to connect the communication line with the specific communication terminal. A bypass switch for direct connection, a switch for switching an impedance between a communication line and the other communication terminal, a switch for switching an amplification factor of an input signal to the other communication terminal, and a call connected to a line to detect a call signal A signal detector, a special signal detector for detecting a special signal identifying the other communication terminal, and a signal controller for controlling switching of each switch according to the output of the call signal detector and the special signal detector. The signal control unit, when the specific communication terminal starts communication, switches the bypass switch to the specific communication terminal and sets the switching switch. Switch to the other communication terminal, the impedance changeover switch to the high impedance side, and the amplification rate changeover switch to the high amplification rate side to enable a special number test mode to enable communication with the specific communication terminal; When the communication terminal starts communication, the changeover switch is connected to the other communication terminal, the bypass switch is turned off, the impedance changeover switch is set to a low impedance side, and the amplification changeover switch is set to a low amplification side. Controlling the switching between a different terminal communication mode enabling communication of another terminal device alone and a specific terminal communication mode in which the changeover switch is connected to the specific communication terminal and the bypass switch is connected to the specific communication terminal. A communication terminal switching control device characterized by the above-mentioned. 2. The apparatus according to claim 1, wherein the amplification rate changeover switch is connected to a high amplification rate side and simultaneously sets a secondary side of a line transformer between the communication line and the other communication terminal to high impedance. Characteristic communication terminal switching control device. 3. A switch in which a specific communication terminal and another communication terminal are both connected in parallel to a communication line, and a switch for switching impedance between the communication line and the another communication terminal, and an input signal amplifier to the other communication terminal A call signal detector that detects a call signal by connecting to a line, a special signal signal detector that detects a special signal signal that specifies the other communication terminal, a call signal detector, and a special signal signal detector. A signal control unit that controls switching of each switch in accordance with the output, wherein the signal control unit sets the impedance changeover switch to a high impedance side when the specific communication terminal starts communication, and switches the amplification factor. A special number test mode in which a switch is connected to the high amplification factor side to enable a special number signal test of the specific communication terminal, and the other communication terminal When starting communication, the impedance changeover switch is set to the low impedance side, and the amplification rate changeover switch is set to the low amplification side to control switching to another terminal communication mode enabling communication of another terminal device alone. A communication terminal switching control device characterized by the above-mentioned.