JPS5844851A - Line switching device - Google Patents

Abstract

PURPOSE:To perform data communication via a network controller, even with the connection to either subscriber telephone lines or exclusive lines, by providing a means which switchingly connects the subscriber telephone lines and the exclusive lines, for a DC circuit of the line side of a network controller. CONSTITUTION:In a line switching device added to a subscriber telephone line data terminal device having a network controller NCU, e.g., an FAX 20, and connected to subscriber telephone lines LN and exclusive lines PL, a DC circuit of a line side of the device NCU is provided with a circuit 30 switchingly connecting the lines LN and PL. Data communication can be done via the device NCU even with the connection to a subscriber telephone line telephone set 13 and a telephone set 14 for exclusive lines. Thus, in switchingly connecting the subscbiber telephone lines or the exclusive lines, the NCU is used in common for the connection of the exclusive lines. Further, at the transmission the line switching is performed manually and at the reception, automatically, allowing to reduce the cost and to simplify the operation without remolding the FAX.

Description

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

Data communications, including facsimile IJ communications, include dedicated communications between specific subscribers using dedicated lines set up by business entities and companies, and subscribed gamma telephone lines (public communication lines).
There is subscriber communication that is carried out between unspecified subscribers using .

When using subscriber telephone lines, various technical standards have been established to prevent interference with telephone and other communications.
For example, when connecting a converter to a subscriber's telephone line and switching between a data terminal and a packing machine, if the data terminal is installed on your own, a line protection device (WPI) may be connected.
It's r.

There are two types of dedicated lines for data transmission: long-distance dedicated lines and local dedicated lines.In local dedicated lines, direct transmission using LH multiplication signals is possible, but in the case of high-speed transmission, there is a lot of noise. Therefore, it is transmitted as an AC signal using a modulation/demodulation device. On long-distance dedicated lines, an amplifier is installed along the way to prevent signal attenuation, and a modulation/demodulation device is used to transmit AC signals.

For example, in order to connect a facsimile device to a subscriber telephone line and transmit facsimile data, the facsimile control unit is usually equipped with a communication control unit (CCU) and a modem unit (MOD).
EM) and network control equipment (N CLJ ) are connected as a set to the subscriber telephone line. The communication control unit provides an interface with the data line, converts serial bit strings on the data line from serial to parallel, matches data signal speeds, performs error checking, detects and inserts control codes, and performs functions such as connection confirmation and termination. Performs the function of transmission control.

In addition, the subscriber telephone line network control device controls the connection of the subscriber telephone exchange network, that is, starts and restores the central office exchange, sends selection signals, detects paging signals, etc., as well as switches to data communication paths and maintains loops. This device has the following functions.

In addition, in order to connect the same facsimile device to a dedicated line to transmit facsimile signals, it is not possible to connect the set for the subscriber telephone line as is, and the network control unit (NCU)
) Instead, a line control device (
It is necessary to connect LCTJ>, and this must be built into the set.

On the other hand, in a 7-aximu IJ for subscriber telephone lines that has a network control device ff (NC1, I), the method of switching the line to a dedicated line is as shown in Fig. 1. As shown in Figure 2, the data line from the modem is connected to the subscriber line by an external switching device between the network control unit (NCU) and the modem in the facsimile. There are cases where the line and dedicated line are switched and connected. That is, in FIG. 1, in the facsimile device wlO, the connection N is transmitted from the facsimile control unit 5 via the communication control unit 4, the modem switching control unit 3, the modem W2, and the network control device w1.
, C is connected to talk lines I and N. External modem for connection to dedicated line PL! 116, and the line switching is performed by the built-in modem device 2 in the modem switching control section 3.
This is performed by switching between the external modem and the external modulation/demodulation device 6. Switching control is performed manually during transmission, and is automatically switched using a code signal in response to an incoming call from a private line PM. In addition, for incoming calls from the subscriber telephone line LN, the network controller t! ■ Received by this phone connected to.

However, in the switching method shown in Figure @1, when switching to the dedicated line PL side, an external modulation/demodulation device 6 is required, which increases the cost accordingly. Further, although analog signals are transmitted from the dedicated line PL to the modulation/demodulation device 6, digital signals are transmitted at the interface between the modulation/demodulation device 6 and the facsimile machine 10, so voice communication cannot be performed over the dedicated line as it is. Usually, a time division device (TDM) is inserted after the modem 6 and a digital telephone is used to make calls.

Furthermore, the facsimile device 10 shown in FIG. 1 is a modified facsimile device for subscriber telephone lines, and the printed board of the modem switching control section 3 is inserted, and the input/output wiring of the modem device 2 and the communication control section 1 is also changed. There is a need. If possible, it is desirable to apply the facsimile device for subscriber lines as is.

Next, in FIG. 2, the modem 2
The external switching device 8 switches and connects the data line between the subscriber telephone line LN and the private line PL. This switching method is mainly used for switching between the subscriber telephone line LN and the international telephone line PI4. !
Manual switch in #8, hybrid coil for 2m-4M conversion] 8, Fatasimile signal level adjustment unit 9 that sends to the international Decil line and international Diedel line.
It is connected to an international digital circuit via an adapter 11. Further, an automatic facsimile receiving unit 12 is provided for converting a call into a digital signal and displaying the incoming call on the facsimile control section 5 when a call is received via the international digital line.

However, the automatic receiving unit 12 for 7 addresses cannot put the facsimile machine ]-0 into the receiving state unless the switch in the switching device 8 is manually switched to the dedicated line side. When the switch is switched to the dedicated line side, the operator of the facsimile machine 10' accepts incoming calls from the international line connected to the international digital adapter 11, and the operator switches the switch on the panel to the dedicated line side. Switch to the line side and press the facsimile reception button to enter reception mode.

A facsimile automatic receiving unit], 2, a signal level adjustment unit 9, and a switching device 8 are combined into one set.

In this way, in the switching method shown in Fig. 2, the subscriber telephone line and the dedicated line are switched at the rear of the network controller @1, so this network controller @1 cannot be shared, and the signal level is Since it is necessary to provide the adjustment unit 9 and also to provide the device 12 for starting reception of the facsimile machine, the cost is high. Furthermore, line switching during reception is not performed automatically, which is extremely inconvenient.

An object of the present invention is to eliminate such drawbacks, and when switching and connecting a subscriber telephone line and a dedicated line, to share the network control device for the subscriber telephone line when connecting the leased line, and to manually transmit and receive data. To provide a line switching device that can sometimes automatically switch lines and reduce costs and simplify operations without modifying a subscriber telephone line data terminal device (for example, a facsimile device).

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 a subscriber 111 talk line and a leased line. The current circuit is provided with means for switching and connecting the subscriber telephone line and the leased line, so that data communication is performed via the network control device even when connected to either the subscriber telephone line or the leased line. There is.

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

FIG. 3 is a system diagram when a 7-axis IJ device is switched and connected to a 2-wire or 4-wire dedicated line using the present invention, and FIG. FIG. 2 is a system diagram in the case where a facsimile device is switched and connected to a dedicated line via a dedicated line.

The line switching device of the present invention uses different interfaces when connecting the leased line depending on the form of the leased line.

In the 31st step, the facsimile machine 20 is connected to the connection point of the 2-line or 4-line dedicated line PL via the line switching device ffi:S'O of the present invention, and the line switching device 30 Switch and connect to four-wire LN. Dedicated line P without any modification to the facsimile device 20 for subscriber telephone line.
Can be connected to L. The line switching device 30 includes a ml line PL.
A main telephone 13 that accepts incoming calls on the subscriber telephone line LN while communicating with the subscriber telephone line LN, and a leased line telephone 14 that responds by voice to an incoming call on the leased line PL while communicating with the subscriber telephone line 1 and N are connected.
In addition, facsimile IJ style! An attached telephone 7 is connected to the network control device in 20.

In Fig. 4, the private branch exchanges 16 are
In this case, an in-band ringer 17 for converting dial pulses into in-band (in-band frequencies 1900 to 24008) is inserted into the leased line.

Of course, in the case of a local dedicated line, in-band, lingua 1
7 is unnecessary. When connecting the 7 axis IJ device 20 only to the private line T)LN via the extension telephone of the private branch exchange 16, the rM connection facsimile device 20 is connected to the extension telephone. On the other hand, when switching connection between the subscriber telephone line LN and the private line PLN, the facsimile machine 20 is connected to the extension telephone via the line switching device 4.0 of the present invention. In addition, line switching equipment M4-0
Connect to subscriber telephone line LN via. In addition, 15
Figure 3 is a detailed configuration diagram of the line switching device shown in Figure 3.

The subscriber telephone line LN is normally connected to the network control device 1 of the 7-axis IJ device 20 via a line switching device 30. ) Join! , 7-acsimile IJ communication on the talk line LN is performed by a subscriber telephone line facsimile device 20 incorporating a normal MA type (manual transmission, automatic reception) network control device 1 for both transmission and reception. if,
Even if the line FIF30 is broken or the power is cut off, the relay contact ns.

(11) Since the subscriber's 1st talk line LN and the 7th axis IJ device 20 are connected on the normal contact side of y, facsimile communication is possible. PD terminal of the facsimile machine 20,
That is, from the data output side of the modem 2 to the line switching device W
Attenuator 26, disconnector 21, line switching device (PD
) 19 to the facsimile device f) 20th PD terminal, that is, the data input side of the network control device, so that the existing terminal of the facsimile device 20 can be used, and the facsimile device F# 20 No modification is necessary.

The transmission level of the signal sent to the subscriber telephone line LN is:
It is adjusted by an attenuator 26.

Next, when transmitting to the dedicated lines PL (4W) and (2W), operate the dedicated line selection switch 25 of the line switching device N3o to drive the sequence control circuit 32 and operate the relays Y and NS. let

When the contact y switches, the M line switching device flt from the modem 2
The attenuation device 26 in 30, the disconnection device 21, and the protection device 19 are released, and are connected to the network control device 1 through a direct path that short-circuits them, and further connects to the network control device 1 through another contact point ys') and 12) to 2. , contact 1% hybrid coil H1 transmission amplifier 39, ψ line attenuator 28, 4-line disconnector 27, and line protection device 22 to 4-wire dedicated line PL r4W
). In that case, the transmission level is $ or device 2
8.

In addition, the transmission amplifier 3q1 hybrid coil H12 line cutter is the unit 23. and line protector 2 via 2 cows
It is made into wire gauze P1 (2W).

The transmission level at this time is corrected by adjusting the gain of the transmission intensifier 39 by the transmission II level that is audible by the hybrid 11, and
It is adjusted according to the number of lines φ of the dedicated line. In this way, at step 1-7, a call I7 to the opposing private line terminal of 4 lines 1' and 2 lines is started. In this case, line switching device 3
0? Even when connecting a dedicated line, the subscriber telephone line LN
The same interface conditions are given to the facsimile machine [20].

When contact nB changes to fjI due to the operation of relay NS, subscriber telephone line L-N is switched to heavy telephone f, 'i machine] 3, and incoming call C3 from subscriber telephone line 14N is switched to main 'M1 telephone machine ■3. Respond with voice. The communication between the subscriber telephone line LN and the main telephone 13 is monitored by a relay Kl, while the communication between the dedicated line PL and the facsimile machine 20 is monitored by a relay 2. When the communication of the facsimile device 20 is completed, the relay 2 uses this to open the contact 2,
Sequence control circuit 32 detects this and restores relays Y and NS. As a result, contacts y and ns are opened and the subscriber's total 1 talk line L N and factor? IJ outfit fl
ff20 is connected and the normal state returns, but if the relay 1 is operating at that time, the contact 1 remains closed, so the sequence control circuit 32 retains the operation of the relay NS, and the telephone 13 is unable to make a call. ensure that

Next, when there is an incoming call from the leased line PL, the call signal (two-wave frequency signal) from the opposing leased line terminal is detected by the detector 29 via the receiving amplifier Il, so the sequence control circuit 32 The control operates relays Y and NS to switch and connect the facsimile machine 20 from the subscriber's 11 talk line LN to the dedicated line PL. That is, both lines are switched and connected by the contact y of the Iu current circuit at the front of the network control device 1, and the contact y of the AC circuit between the modem w2 and the network control device I# is used to connect the two lines in the same way as during transmission. Then, the attenuator 26, the disconnector 21, and the line protection device t1.9 are disconnected to form a short circuit path. After connection, relay SG2
oscillator 3 to the facsimile machine W20.
By transmitting a paging signal of 1 to 16H2, the facsimile machine 20 shifts to a receiving state.

In addition, after connecting to the dedicated line PI4 and immediately before starting communication,
Activate relay CA [7 to close contact ca and form a receiving path. When the facsimile machine [20 is communicating with the subscriber telephone line LN and a call is received on the dedicated 'mPL, the sequence control circuit 32 activates the relay SG1 to connect the dedicated line! , calls the filling machine 14.

When the leased line operator goes off-hook, relay L detects this and drives the sequence control circuit 32, operates relay X, closes contact X, and responds with voice to the opposing leased line. . Also, a fax machine! 20 is communicating with subscriber telephone line 1, N, leased line 1)
(15) When the operator is absent, the sequence control circuit 32
detects the signal from the detector 29 and the closing of contact kl in monitoring relay 1, and operates relay S G 3 to close contact s.
It is also possible to close g3 and send the busy tone from the signal generating circuit 38 to the dedicated line PL.

Further, the signal generation circuit 38 generates a selection signal and sends it to the dedicated line PL at the time of a call. Note that the calling signal of 16H2 is sent from relay SG1. When either SG2 operates, the message is sent to one of the dedicated line telephones 144 and facsimile machines 2o.

In this way, by using the line switching device 30 shown in FIG. 5, the network control device 1 with a built-in facsimile can be shared with subscriber telephone lines ① and N and dedicated MPL, so that the subscriber telephone line factor t IJ There is no need to modify the equipment. Further, level adjustment during transmission to subscriber telephone line LN and private line PL is performed using separate attenuators 26. ．． 28, line protection equipment f! 1ffi19, 22, 24 and the cutoff can be done by connecting the vessels 21, 24 and 27 separately according to the standard (16). Note that the dotted connection lines of Hybrid H are the points where parts are disconnected during construction or delivery testing, and where they are connected.

FIG. 6 is a detailed configuration diagram of the line switching device shown in FIG. 4.

In this case as well, the subscriber line and voice line LN are normally connected to the network control device 1 of the facsimile machine 1t20 via the line switching device 40. The route for communicating with subscriber telephone line #LN is exactly the same as that shown in FIG.

Next, when transmitting on the dedicated line side (extension of a private branch exchange, hereinafter referred to as PBX extension), first operate the changeover switch 25 to drive the sequence control circuit 33 and operate the relay Y1. Switch contact y1 and use facsimile! 20 to the dedicated line PL. That is,
Contact y1) of the DC circuit at the front of the network control device fW1 switches and connects the twisted line, and also connects the terminal 11' of the facsimile machine 120, that is, the data output side of the modem [2] and the data input side of the network control device 1. an attenuator 26 connected to the AC circuit of . The cutoff is the device 21 and the line protection device t (
The PD) 19 is disconnected by the contact y0, and connected to the path to which the dedicated line attenuator 37, disconnector 36, and line protection device 35 are connected. However, in this case, when it is a local leased line, the short circuit is separated by the X mark, and the attenuator 37 and the disconnector 36 are used to adjust the transmission level to the leased line.
, via the line protection device 35 [7], and in the case of a dedicated long-distance line, construction will be carried out so that the signal will be transmitted via the short-circuit path without disconnecting it at the X mark. In the case of a dedicated long-distance line, level adjustment and line protection are performed within the in-band ringer 17 shown in FIG. 4, so there is no need for () on the extension side.

After the facsimile machine ff20 is connected to the PBX extension,
Using the attached telephone 7, the user confirms the dial tone of the PBX extension and performs a dialing operation to call the terminal on the opposite leased line. P
After the BX sends a ring tone, communication begins when the other party is connected. - During communication with the PBX extension, contact n8 switches due to the operation of relay NS, so the subscriber telephone line LN is connected to the main telephone 14, and incoming calls from the subscriber telephone line LN are answered with voice by the main telephone 14. do.

As in the case of FIG. 5, communications with the leased line are monitored by relay 2, and calls with the subscriber line LN are monitored by relay K1. irl with January 11 line! When the signal ends, relay K2 detects this and the sequence control circuit 33 returns relay Y1 to shift axis IJ.
The device 20 is switched and connected to subscriber 1's line LN,
Relay NS is not restored while relay Kl detects that a call is in progress.

Next, if there is an incoming call from the dedicated line side (PBX extension),
The ringing detection circuit 34 detects the l fl H2 calling signal sent to the PBX extension.

Here, the ring trip is not performed, but the relay Yl is operated under the control of the sequence control circuit 33, and the contact y
0 by 7 Aximi IJ Sojo 20 subscribed telephone line LN
Switch and connect to the dedicated line. After the switching connection, the calling signal of 1614□ from the PBX extension is sent to the facsimile machine 20 as is. As a result, the facsimile device ff20 shifts to the reception α9) state. In addition, in the same way as when transmitting, relay NS
operates, switches the contact ns, and when a call is received from the subscriber telephone line LN, a voice response is made from the main telephone field 1. Also, busy monitoring on the subscriber telephone line side is performed by relay 1, and communication monitoring on the leased line side is performed by relay 1 (2).

Furthermore, if a call is received on the PBX extension while the facsimile machine 20 is communicating with the subscriber telephone line LN, the sequence control circuit 33 indicates that communication is in progress by operating relays K and 1.
is detected, relay Y2 is operated, contact point y is switched, and the extension caller 15 makes a voice response.

As claimed above, according to the present invention, line switching between the leased line and subscriber telephone line is performed by the line side DC circuit which is the front part of the network control device, so that the subscriber telephone line is switched.

The network control device for the interrogation line can also be used for the dedicated line, and line switching can be performed without any modification to data terminal equipment such as facsimile machines. In addition, by using the line switching device of the present invention, it is possible to provide the same interface conditions as the subscriber telephone line even in a leased line connection, and to manually select the line when transmitting. Switching can be performed automatically, and even if the line switching device fails or the power is cut off, the
Communication is possible because it is based on connection from the subscriber phone perspective. Note that the present invention is not limited to facsimile, but can also be applied to general data communication.

[Brief explanation of the drawing]

1 and 2 are block diagrams showing conventional line switching methods, FIG. 3 is a block diagram also showing a first embodiment of the line switching device of the present invention, and Figure 4 is a block diagram showing the line switching device of the present invention. FIG. 5 is a detailed configuration diagram of the line switching device shown in FIG. 3, and FIG. 6 is a detailed configuration diagram of the line switching device shown in FIG. 1: Network control device, 2: Modulation/demodulation device, b; Facsimile IJ
Control unit, 7: Attached telephone, 13 = Subscription inquiry line Main telephone, 14 + Dedicated line ¥1. Packing machine, 15+ extension telephone, 16+
Private branch exchange, 17: In-band ringer, 19.22.
24.35 + line protection device, 20: facsimile machine, 21, 23.27, 36: cutting device, 26.28
．． 37: Attenuator, 2Gl ring signal detector, 30.4 (
1 line switching device, 31: ], 6 to 1□ signal generator, 32.33F sequence control circuit, 34. : I.J.
ringing detection circuit 38 two selection signals, busy signal generator;
39, 41: Transmission and reception amplifiers.

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 a leased line, a direct current on the line side of the network control device is provided. The circuit is equipped with a means to switch and connect the subscriber 4-phone line and the dedicated line, so that data communication is performed via the 1-wiring control device regardless of whether it is connected to the subscriber city 5-phone line or the leased line. A line switching device characterized by: 3) In a line switching device that is added to a subscriber telephone line data terminal device having a network control device and is connected to a subscriber telephone line and a leased line, the subscriber telephone It has a means for switching and connecting the line and the leased line, and connects an attenuator for adjusting the signal level sent to the subscriber telephone line, a line switching device, and a disconnector to the AC circuit on the data terminal side of the E wiring control device. A line switching device characterized in that when connecting to a leased line, the attenuator, line protection device, and disconnector are short-circuited and the line is routed through an attenuator or the like for the leased line. (3) The means for switching and connecting the subscriber telephone line and the leased line is such that in normal times, the network control device is connected to the subscriber telephone line and the subscriber telephone line. Line switching device described in Section 2. (4) The above-mentioned means for switching and connecting the subscriber telephone line and the leased line connects the subscriber telephone line to the leased line and at the same time switches and connects the subscriber telephone line to the telephone set, and responds by voice to an incoming call from the subscriber ηf telephone line. A line switching device according to claim 1 or 2, characterized in that: (5) The above-mentioned means for switching and connecting the subscriber telephone line and the leased line constantly monitors the communication between the subscriber telephone line and the leased line, and while communication is detected, other communications are not performed. 3. The line switching device according to claim 1, wherein the line switching device does not continue switching even after the switching period has elapsed.