JPS6259501B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a line switching device, and more particularly to a switching device between a dedicated line and a subscriber telephone line in data communications.

Data communications, including facsimile communications, include dedicated communications between specific subscribers using dedicated lines set up by business entities and companies, and communications between unspecified subscribers using subscriber telephone lines (public communication lines). There is a subscription communication that takes place between.

When using a subscriber telephone line, various technical standards have been established to prevent interference with telephone and other communications. When using switching and installing data terminals on your own, you are supposed to connect a line protection device (PD).

To connect a facsimile device to a subscriber telephone line and transmit facsimile signals, the facsimile control unit is usually connected to a communications control unit (CCU), modem (MODEM), and network control unit (NCU).
Connect to subscriber telephone line.

Conventionally, when using the same facsimile device by switching between a subscriber telephone line and a leased line, it was not possible to use the network control unit (NCU) for the subscriber telephone line as is for the leased line, so it was necessary to select the one for the leased line. It was necessary to separately connect a line control unit (LCU) with functions such as signal transmission, ring signal detection, switching to a data communication path, and switching with a telephone attached to a leased line. Furthermore, in order to switch between the subscriber telephone line and the leased line, it is necessary to provide other special equipment, resulting in high costs. Furthermore, since line switching is not performed automatically when receiving,
This is extremely inconvenient.

Therefore, when switching and connecting the subscriber telephone line and the leased line, the present inventor shared the network control device for the subscriber telephone line when connecting the leased line, and the data terminal device (for example, a facsimile machine) for the subscriber telephone line was used. We have previously proposed a line switching device that can be used without modification (see specification of Japanese Patent Application No. 114585/1983). That is, as shown in FIG. 1, the above-mentioned line switching device 1 is added to the facsimile device 3, and
By providing a switching contact y in the DC circuit on the line side of the network control device 31 built into the network control device 31 to switch and connect the subscriber telephone line LN and the dedicated line PL, no matter which one is connected, the connection can be made via the network control device 31. I'm trying to do facsimile communication. Under normal circumstances, switching contact y is connected to the subscriber telephone line LN side, but when a call is received on the leased line PL and the facsimile machine is not communicating, the control circuit 6 controls the switch contact y to connect to the leased line PL side. Switch to
The facsimile device 3 is connected to the private line PL, and the contact x is switched to the main telephone 2 side, so that incoming calls from the subscriber telephone line PL are answered with voice.

However, in the line switching device 1 shown in FIG. 1, the facsimile device 3 is always connected to the subscriber telephone line LN, so when sending a facsimile to the subscriber telephone line LN, the selection switch must be pressed. However, when sending a facsimile to the dedicated line PL, the control circuit 6 is activated by operating the selection switch 7 and the contact y is switched before sending, which saves time and effort. And it takes time. In addition, dedicated line
If multiple data terminals similar to those shown in Figure 1 are connected to the PL, there will be competition among them, so it will be difficult to obtain the right to transmit even if you try to make a call, and if the dedicated line PL is not available, you will not be able to send. Sometimes. Furthermore, when a telephone connected to the leased telephone line LN hangs up, the public telephone exchange sends a howler tone to the telephone, but when a telephone connected to the leased line PL hangs up, When this occurs, all data terminals connected to the leased line PL will be unable to make or receive calls because there is no countermeasure against it.

The purpose of the present invention is to eliminate these conventional drawbacks, and in order to eliminate these conventional drawbacks, when the line is not in use, it is necessary to
Instant data transmission is possible by simply turning off the attached telephone without operating a switch, etc., and the next call can be reserved even if another competing terminal is connected to the dedicated line. Another object of the present invention is to provide a line switching device that can minimize the influence on others even when a telephone connected to a dedicated line takes the receiver off the hook.

The line switching device of the present invention is a line switching device added to a subscriber telephone line data terminal device having a network control device and connected to the subscriber telephone line and the leased line. The present invention is characterized in that means is provided for detecting that the telephone has gone off-hook, and based on the output of the detection means, the subscriber telephone line data terminal device is connected to the line corresponding to the off-hook telephone. Further, the line switching device of the present invention is provided with a subscriber telephone line switch, a leased line switch, and means for detecting that these switches are operated, and the line corresponding to the operated switch is connected based on the output of the detecting means. It is characterized by connecting a telephone line data terminal device. Further, the line switching device of the present invention is provided with a dedicated line reservation switch and a means for detecting that the switch is operated, and when the reservation switch is operated while the dedicated line is busy, the time when the dedicated line becomes vacant is determined. It is characterized by sending a signal to the leased line for a preset period of time, prohibiting calls from other terminals connected to the leased line, and giving priority to calls. Furthermore, the line switching device of the present invention is provided with a reset signal sending means, a howler sound sending means, and a receiver disconnection detecting means, and when the detecting means detects that the telephone connected to the leased line is disconnected from the receiver, the line switching device resets the telephone to the leased line. It is characterized by transmitting a signal to reset the prohibition of calls from other terminals, and transmitting a howler sound to the telephone when the receiver is off the hook.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a connection system diagram of a dedicated line system using the line switching device of the present invention.

The line switching device 10 of the present invention has a function of connecting the subscriber telephone line facsimile device 3 and the leased line PL, and thereby performs leased line facsimile communication using the subscriber telephone line facsimile device 3. Can be done. In addition, the line switching device 10
has a switching function between the subscriber telephone line LN and the leased line PL, and by automatically switching when receiving, and selectively switching by off-hook of the telephone when sending, it is possible to switch between facsimile communication using the subscriber telephone line network, and
The aforementioned dedicated line facsimile communication is possible.

The connection form of the private line PL is, for example, a bidirectional branch line as shown in FIG. 2, and a four-wire private line can be used. Phone 2 in each terminal
is a facsimile destination selection telephone (this telephone), telephone 5 is a conversation telephone, and telephone 4 is a conversation telephone.
is a telephone attached to a leased line.

The basic mode of line connection of the line switching device 10 is as follows:
It is in the subscriber telephone line mode, and becomes the leased line mode by receiving a call from the leased line PL or by performing an off-hook operation on the attached line telephone 4.

Telephones 4 and 5 of each terminal connected to the dedicated line PL
By dialing a preset dial number using the pushphone, it is connected to the facsimile device 3 or conversation telephone 5 of any other terminal, and facsimile communication and telephone calls can be performed.

FIG. 3 is a block diagram of a line switching device showing an embodiment of the present invention.

(1) First, telephone calls and facsimile communications using subscriber telephone line LN will be explained.

In a normal state, facsimile device 3 is connected to subscriber telephone line LN, and relays CN1 and CN2 are not operating at this time. Telephone calls and facsimile communications on subscriber telephone line LN are monitored by relay TA and relay TT. In other words, if both relays TA and TT are operating, the phone 2 is communicating via facsimile device 3, and if only relay TA is operating, it is controlled to indicate that facsimile communication is in progress. Circuit 11 identifies. Of course,
It is also possible to replace TA and TT with photocouplers, semiconductors, etc. instead of relays.
Now, when you take off phone 2 to send a message, phone 2 - switch SW1 - relay TT
A DC loop is formed along the path of - TL terminal of the facsimile machine - LN terminal - Relay TA - Switch SW1 - Line LN, and relays TA and TA operate. This closes contacts tt and ta, but in control circuit 11, relays CN1 and CN2 do not operate because switches SW3 and SW4 are in the OFF state.

After calling the other subscriber from the telephone 2 and notifying the subscriber of facsimile transmission, the subscriber telephone line LN is reconnected to the facsimile device 3 by on-hooking the telephone 2. That is,
Subscriber telephone line LN - Switch SW1 contact cn1 - Relay TA - Facsimile device LN terminal - PD terminal - Contact cn2 - PD (line protection device) - Contact cn1
- PD terminal - network control device 31 - modem device 32
- Facsimile transmission is performed through the route of the facsimile control unit 33.

Next, when a call arrives on the subscriber telephone line LN, the facsimile device 3 performs ring detection through the above route, and the DC loop is maintained, so the relay
TA works. The operation of relay TA closes contact t _a to start control circuit 11, and relay CN
1 to switch contact cn1 and call this telephone 2. After the operator answers using the telephone 2, the operator switches to the facsimile device 3 and receives the facsimile.

(2) Next, manual line switching will be explained.

The line switching device 10 of the present invention is provided with manual changeover switches SW1 to SW4. SW
1 is switching between this telephone and line switching device, SW2
is a leased line reservation switch, SW3 is a leased line switch, and SW4 is a subscriber telephone line switch.

When subscriber telephone line LN is in use by telephone 2 but no facsimile communication is being performed, if you wish to connect facsimile device 3 to dedicated line PL, off-hook telephone 4 attached to the dedicated line, and Dedicated line switch SW3
Turn on. The control circuit 11 first includes a relay.
By operating CN1 and switching contact cn1, facsimile device 3 is completely disconnected from subscriber telephone line LN, and relay CN2 is operated with a slight (250 mS) delay time. As a result, facsimile device 3-contact cn2-
It is connected to the dedicated line PL through the photocoupler TB1 - contact rg ₁ - contact ll ₁ - transformer attenuator ATT -...

Next, when the leased line PL is being used by the attached telephone 4 but no facsimile communication is being performed, if you wish to connect the facsimile device 3 to the subscriber telephone line LN, you must off-hook this telephone 2 and , subscriber telephone line switch
Turn on SW4. As a result, the control circuit 11
First, relay CN2 is restored, and after a short (250 mS) delay time, relay CN1 is restored. The attached telephone 4 is connected to the dedicated line PL via the contact cn2. On the other hand, the facsimile device 3 is relay TA - contact cn1 - switch SW
1 - Connected to subscriber telephone line LN via the route LN.

(3) A call from the dedicated line attached telephone 4 will be explained.

When attached telephone 4 is off-hook when both lines are not in use, telephone 4 - Photocoupler TF - Contact cn2 - Photocoupler TB1 -
The photo couplers TF and TB1 are turned on by the direct current path of the power supply voltage (+24V) connected to the contact rg ₁ -contact ll ₁ -transformer, the terminals a and b become ground potential, and the control circuit 11 is activated.

The control circuit 11 operates the relay CN2,
By switching contact cn2, attached telephone 4 - photo coupler TF - contact cn2 - TL terminal - LN terminal - contact cn2 - photo coupler TB1
-... is formed, and the attached telephone 4 is connected to the dedicated line PL via the facsimile device 3.
Next, the relay LR is operated for a short time, the contact _lr is switched, and the oscillator 14 sends out a lock signal of two frequencies (for example, 1027.5 Hz and 592.5 Hz) to the dedicated line PL. This prevents calls from other terminals. Next, a dial tone is sent from the oscillator 13 to the attached telephone 4.
Press the push button to stop the dial tone.

If the dedicated line PL is in use, a lock signal is input, so the detector 12 detects this and operates the relay LL, which connects the oscillator 13 - amplifier AMP - (A) - contact ll ₁ −
A visit tone is sent out along the route of contact rg ₁ - photocoupler TB1 - contact cn2 - photocoupler TF - telephone 4.

At the time of facsimile transmission, the photocoupler TF is turned off by the on-hook of the telephone set 4, and only the photocoupler TB1 remains on.

When the call or facsimile communication ends,
The photo couplers TF and TB1 are turned off, the control circuit 11 operates the relay LR, and the oscillator 14 transmits two frequencies (for example, 1027.5Hz,
502.5Hz) reset signal. In addition,
Relays and other semiconductors can also be used in place of the photocouplers TF and TB1.

(4) The case of making a call using the conversation telephone 5 will be explained.

When the telephone 5 is off-hooked, the photocoupler TB2 is turned on and the terminal c becomes the ground potential, so the control circuit 11 is activated, and after sending a lock signal to the dedicated line PL as described above, the lock signal is sent to the telephone 5. Sends a dial tone. In this case, the operation is the same as that of the telephone 4 except that it is not connected to the facsimile device 3.

(5) The case where the attached telephone 4 receives a call will be explained.

A selection signal for telephone 4 from another terminal (e.g. 2
When the digit) is sent out, the detector 12 detects it, operates the relay RG ₁ , and the ringing tone generator 15 transmits the signal to the telephone 4 via the contact RG ₁ .
Sends a call signal to. While the calling signal is being sent, the oscillator 14 sends a ring back tone to the calling side.

When you take off the attached telephone 4, the relay
When RG ₁ is restored, it stops sending out ringback tones and a communication path is established, allowing telephone or facsimile communication.

It should be noted that even when a call is received from another terminal to the conversation telephones 5, 5', it is exactly the same as receiving a call to the attached telephone 4, except that the facsimile device 3 is not connected.

Other unnecessary incoming calls are disconnected from the DC supply transformer by operating relay LL and opening contacts _ll1 to _ll3 .

(6) Explain what happens when the dedicated line reservation switch is turned on.

Reservation switch SW when dedicated line PL is in use
When 2 is turned on, the control circuit 11 immediately sounds the buzzer for a predetermined period of time (for example, 30 seconds), flashes the lamp 17, and turns on the relay LR for that period. When activated, the oscillator 14 sends a lock signal to the dedicated line PL. This makes it possible to prohibit other terminals from making calls and to give priority to making calls during the prohibition period.

In addition, reservation switch SW2 can be used on multiple terminals.
In order to avoid conflicts when the terminal is turned on, priorities are set for all terminals, and the lock signal is sent after waiting for a different amount of time depending on the priority. For example, a terminal with the highest priority will send a lock signal 0 seconds after the current communication ends.
The lock signal is sent for 30 seconds, and the terminal in the next rank sends a lock signal 3 seconds after the end, and the terminal in the third rank sends a lock signal 6 seconds after the end. As a result, among the terminals that have turned on the reservation switch SW2, the terminal with the highest priority obtains the next right to make a call.

(7) Explain the case of disconnecting the handset.

If one of the telephones 4, 5, 5' of each terminal goes off the hook, the lock signal sent from that terminal makes the other terminals unusable. Therefore, the control circuit of each terminal counts a certain amount of time (for example, 32 seconds) with a counter when the telephone 4, 5, 5' goes off-hook.
If the push button is pressed twice within this time, it is assumed that the transmission is normal and the howler sound transmission is stopped. However, if the push button is not pressed at all or is pressed only once within this time, the oscillator 13 Sends a reset signal to the dedicated line PL to cancel the prohibition of calls from other terminals.
In other terminals that received the reset signal, detector 1
By detecting this in 2, relay LL1
-Restore LL3, switch contacts _ll1 to _ll3 , and stop sending out the busy tone.

The terminal that sent the reset signal to the dedicated line PL operates one of the relays LL1 to LL3 and connects the oscillator 13 - amplifier AMP - (A) - contacts ll _{1 to 3} .
- Contacts rg _{1 to 3} - Photo couplers TB1 to 3 - Telephones 4, 5, and 5' are used to send out howler sounds. In this case, the howler sound is amplified to a considerably high level by the amplifier AMP.

It should be noted that identification of press button depression within a certain period of time (32 seconds) is performed by detecting a leakage (low level signal) on the receiving terminal side of the hybrid 16 with the detector 12.

Further, when the telephones 4, 5, 5' are in an off-hook state and the reservation switch SW2 is turned on (buzzer on), the howler sound sending circuit does not operate.

In addition, manual operation (button operation) allows data communication on one line while a call is in progress on the other line, and a dedicated line reservation switch allows you to receive priority for the next call when the current communication ends. It goes without saying that the functions that can be applied to the line switching device shown in FIG. The invention first proposed a line switching device (patent application 1983-
114585)).

As explained above, according to the present invention, the same data terminal can be connected to either the subscriber telephone line or the leased line by simply off-hooking the attached telephone, eliminating the need for manual operations such as switches. Instant data transmission is possible. In addition, by providing a leased line switch, subscriber telephone line switch, or reservation switch, data communication can be performed on one line even while a call is being made on the other line, and even if the leased line is currently in use, the next You can reserve priority calling. Furthermore, since it detects when the handset is disconnected, it sends out a howler sound and cancels the prohibition of calls from other terminals, so even if the handset is disconnected, the impact on the leased line system can be minimized. . Note that the present invention is not limited to facsimile, but can also be applied to general data communication.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of the previously proposed line switching device, Fig. 2 is a connection system diagram of a dedicated line system using the line switching device of the present invention, and Fig. 3 is a line switching diagram showing an embodiment of the present invention. FIG. 2 is a block diagram of the device. 1, 10: Line switching device, 2: This telephone, 3:
Facsimile device, 4: Telephone with dedicated line, 5,
5': conversation telephone, 6, 11: control circuit, 7:
Selection switch, 12: Signal detector, 13, 14:
Oscillator, 15: Ringing tone generator, 16:
Hybrid coil, 17: lamp, 31: network control device, 32: modulation/demodulation device, 33: facsimile control section.

Claims (1)

[Scope of Claims] 1. In a line switching device added to a subscriber telephone line data terminal device having a network control device and connected to the subscriber telephone line and the leased line, the status of each telephone corresponding to the connected line A line switching device characterized in that the state monitoring means detects an off-hook of a telephone and connects the subscriber telephone line data terminal device to the line corresponding to the off-hook telephone. 2. Means for monitoring the status of each telephone corresponding to the connected line in a line switching device added to a subscriber telephone line data terminal device having a network control device and connected to the subscriber telephone line and the leased line;
A manual switch corresponding to the connected line is provided, and by operating the manual switch, the data terminal device for subscriber telephone line can be connected to the vacant line corresponding to the off-hook telephone, regardless of the call status of other lines. A line switching device characterized by connecting. 3. The means for monitoring the state of each telephone also monitors the communication state of the data terminal device for the subscriber telephone line, and when the terminal device is in communication, it does not switch and connect even if the manual switch is operated. A line switching device according to claim 2. 4. Means for monitoring the status of each telephone corresponding to the connected line in a line switching device added to a subscriber telephone line data terminal device having a network control device and connected to the subscriber telephone line and the leased line;
A leased line reservation switch is provided to reserve priority calling when the leased line becomes vacant among the connected lines, and by operating the leased line reservation switch while the leased line is busy, the call can be made in advance from the time the leased line becomes vacant. A line switching device characterized in that a call prohibition signal is transmitted to the dedicated line for a specified period of time. 5. A line switching device attached to a subscriber telephone line data terminal device having a network control device and connected to the subscriber telephone line and the leased line, monitors the status of each telephone in its own terminal corresponding to the connected line. and a means for detecting that the telephone in the own terminal which is off-hook and connected to the leased line does not send a selection signal within a predetermined time, and the detecting means detects when the telephone in the own terminal is disconnected from the receiver. A line switching device characterized in that, when detected, it sends a call prohibition state release signal to the leased line, and also sends a howler sound to the telephone set in which the disconnection of the handset is detected.