JP3108246B2 - Data communication system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention uses a no-ringing service for performing automatic meter reading and tele-control of gas, water, etc. by a no-ringing communication from a general subscriber telephone line to an extension of a private branch exchange such as an apartment house or a company. The present invention relates to a data communication system for performing data communication between a communication terminal and a center via a telephone line.

[0002]

2. Description of the Related Art Conventionally, no ringing communication is used between a center-side device and a terminal device connected to an extension of a private branch exchange (hereinafter referred to as a PBX) such as an apartment house via a terminal network control device. In a data communication system that performs meter reading and the like, there are Japanese Patent Application Nos. 3-26003 and 4-4443 as prior arts.

In the former, a PBX to which terminal equipment is connected
A sub-center directly called from the center-side device via the public network is connected via an extension, and the former sub-center is configured to perform data communication between the terminal device and the center-side device independently of the PBX. I have.

[0004] In the latter case, when the PBX makes a no-ringing call to an extension, even if the terminal network control device that made the no-ringing call goes on-hook, it does not release the incoming telephone line, and does not release the no-ringing call from the calling side. It is configured to wait until there is a designation of the extension to be performed or to send a signal to the calling side requesting the next extension to be called.

[0005]

In THE INVENTION to be solved INVENTION The above prior art line cormorants system data communication performing non-ringing call to the center network control apparatus which is provided in the center side in the apparatus P
When the signal from the BX cannot be received due to noise or the like, or when the response signal of the center network control device cannot be received by the PBX in response to the signal from the PBX, both units operate on-hook due to timeout, so that smooth operation is performed. could not. In addition, when a telephone is connected to the terminal network control device, even if an attempt is made to use the telephone during communication between the terminal equipment and the center network control device, the telephone cannot be used because the switching cannot be performed.

Also, when a call from the center network control device to the terminal network control device is used, the line on the terminal network control device side is in use.
When the terminal network controller is communicating with another center network controller, no response from the terminal network controller, a call from the terminal network controller, etc., the center network controller can grasp these situations. Did not.

Further, when the telephone of the terminal network control device is in use, it is not possible to eliminate the influence of noise or the like when transmitting the signal to the center network control device.

In view of the above problems, the present invention has
It is an object of the present invention to provide a data communication system which grasps a communication state between various terminals connected to X and a center and enables bidirectional data communication without being affected by noise.

[0009]

The object of the present invention is to provide one or more terminal network controllers 3 to which a terminal device 1 and a telephone 2 are connected, and to the terminal network controllers 3 via an extension. And a center network controller 6 connected to the PBX 4 via a telephone line 5. Data communication is performed between the center network controller 6 and the terminal network controller 3 by means other than the PB signal. Means for transmitting and receiving a PB signal used as a response signal between the PBX 4 and the center network controller 6 or the terminal network controller 3;
Means for interpreting the combination of B signals, for example, the meanings of "1 + 0" and "1 + 1"; means for periodically transmitting a PB signal until there is a response from the other party; and PB signal transmitted periodically. Means for responding to a call from the center network control unit 6 after the off-hook for a call from the center network control unit 6; Means for adding a signal indicating that the call is from the terminal network control device 3 before the dial signal of the telephone set 2, and when the telephone 2 is off-hook during communication between the center network control device 6 and the terminal network control device 3. Means for connecting the line to the telephone 2.

[0010]

In the above means for solving the problems, during the communication regardless of the call from the center network control device 6 or the call from the terminal side, the PBX signal is output until the PBX 4 responds to the center network control device 6. Will be sent out. Therefore, the center can understand the current state of communication by interpreting the contents of the PB signal. For example, when a connection cannot be established due to the influence of noise or the like, communication is continued by taking action to avoid the influence of noise on the center side, and the need to perform an on-hook operation due to a timeout is eliminated. Further, the contents of the PB signal allow the center to grasp the situation such as the use of the line, the communication with another center network control device 6, the call from the terminal, and the like.

When the extension telephone 2 is used during data communication between the center network controller 6 and the terminal network controller 3, the PBX 4 uses the PB signal to indicate that the telephone 2 has been taken off-hook. The network controller 6 is notified and the line is switched to be connected to the telephone 2 so that the telephone 2 can be used at any time.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a data communication system according to the present embodiment has a plurality of terminal network controllers (hereinafter referred to as T-NCUs) to which a communication terminal 1 having a communication function such as a microcomputer gas meter and a telephone 2 are connected. ) 3, a PBX 4 connected to the T-NCU 3 via an extension, and a center network controller (hereinafter referred to as C-NCU) 6 connected to the PBX 4 via a general telephone network 5. Performs a no-ringing call to the T-NCU 3 connected to the extension designated by the calling side, and makes the C-NCU 6 and the T
-Data communication with the NCU 3. Note that the C-NCU 6 includes one connected to the outside line of the PBX 4 and one connected to the inside line of the PBX 4.
The host computer 7 is connected to U6.

FIG. 2 shows the configuration of the T-NCU 3. In FIG. 2, 10 is a line transformer, 11 is a modem, 12
Sends a PB signal to the telephone line or PB from the telephone line
A transmission / reception circuit for receiving a signal; 13 a line side circuit for controlling a telephone line; 14 a circuit for switching connection of a telephone to a line and monitoring whether the telephone is off-hook; 15 a modem 11 and each circuit , A reference circuit 16, an interface circuit, 17 a power supply circuit, 18 a memory, 19 a changeover switch for forcibly connecting a line to the telephone, and 20 a reset circuit.

Further, T-NCU3 and C-NCU6
Uses a PB signal for the PBX 4, and performs data communication between the C-NCU 6 and the T-NCU 3 using FSK or the like. And C-NCU6, T-NCU3, PB
X4 has a built-in microcomputer.
It has transmission / reception means for transmitting / receiving the B signal, and determination means for interpreting the contents included in the PB signal.

In addition to the above-mentioned means, the T-NCU 3 has a call identification means for adding an identification code indicating a call to the dial signal to the PBX 4 when making a call, and the telephone 2 is off-hook during communication. When the off-hook notification means for notifying the PBX 4 by hooking and a pre-ringer signal from the PBX 4 (a ringer having a different cycle may be transmitted before a normal-cycle ringer, this is called a pre-ringer) are transmitted. A telephone means for connecting a line to the telephone 2 is provided.

After the end of communication, the PBX 4 has a C-NCU 6
And a disconnection notifying means for periodically transmitting a PB signal until a response signal is received from the terminal, and detecting when a no-ringing call to the T-NCU 3 and a call from the T-NCU 3 or a call from the telephone 2 collide. When the connection from the C-NCU 6 cannot be connected to the T-NCU 3 in response to a call from the C-NCU 6, a combination of PB signals (for example, “1”)
+0 "and" 1 + 1 ") to express the reason and C-N
The T-NCU 3 is in communication with the connection disable notification means for transmitting to the CU 6, the line use notification means for periodically transmitting a PB signal different from the PB signal by the disconnection notification means when hooking is detected by the off-hook notification means, and Even if the telephone 2 is off-hook, the line switching means for connecting the line so that it can be used, and whether or not to transmit the pre-ringer signal twice at a certain interval to the T-NCU 3 to execute the pre-ringing service and the pre-ringing setting means is caused to Yes for setting whether.

The C-NCU 6 has a response means for transmitting a response signal to the PBX 4 when the periodic PB signal transmitted from the PBX 4 is in a pause state.

Next, data communication when making a call from the C-NCU 6 shown in FIG. 3 will be described. First, the host computer 7 specifies the PBX 4 to the C-NCU 6 and
A selection number (hereinafter, referred to as a first dial) indicating an incoming call to NCU 3 and a selection number (hereinafter, referred to as a second number) indicating designation of a PBX extension line and T-NCU designation on the line.
(Called a dial) as information. The C-NCU 6 performs the first
Send the dial to PBX4.

As a result, when the C-NCU 6 is on the outside line side of the PBX 4, the call is received by the PBX 4 via the general telephone line network 5 by a dial-in line or a dedicated line, and when the C-NCU 6 is on the extension line side, the call is directly received by the PBX 4. here,
Preliminarily PBX 4 the system data set, if defined as a dial-in number is meant incoming call to T-NCU 3, it is easy to distinguish the normal telephone call to PBX 4.

Then, the PBX 4 that has received the call by the first dial can periodically transmit a request signal (PB signal) of the second dial to the C-NCU 6 because it can know that the call has arrived at the T-NCU 3.

As shown in FIG. 4, the PBX 4 is in the receiving state during the gap time T2 during which the intermittent PB signal is not transmitted, and waits for the response PB signal from the C-NCU 6. At this time, the PBX 4 stops sending if a suitable response PB signal is received from the C-NCU 6, and knows that the contents of the PB signal have been correctly recognized by the C-NCU 6. On the other hand, if the PB signal stops coming, the C-NCU 6
, The response PB signal transmitted by the user is correctly recognized. The response PB signal at this time may be used as a command for instructing the PBX 4 to perform the next operation.

C-NC that has received the second dial request signal
U6 sends out the second dial. When the PBX 4 receives the second dial, it sends out a start signal with the T-NCU selection number to the corresponding extension line according to the contents.

[0023]

The T-NCU 3 having received the activation signal, if the selection number indicated by the activation signal corresponds to itself, the P-NCU 3
A response signal (off-hook) is sent to X4, and communication terminal 1 is activated. Upon receiving this response signal, the PBX 4 transmits a connection completion PB signal to the C-NCU 6.
Then, the C-NCU 6 outputs to the host computer 7 a connection completion signal indicating that communication is possible. Thereby, data communication is performed between the communication terminal 1 and the host computer 7.

When the data communication is completed and the T-NCU 3 goes on-hook first, the PBX 4 does not perform a recovery operation on the center line, and outputs a disconnection PB signal indicating the state.
-Periodically transmitted to the NCU 6, and waits for the next operation instruction.

The C-NCU 6 sends a disconnection signal to the host computer 7, and the host computer 7 sends the PBX 4
A response signal including a command indicating the next operation to the C-NC
Send to U6. Then, the C-NCU 6 sends out the response PB signal at a time interval between the PB signals from the PBX 4. Response P
The PBX 4 that has received the B signal sends an activation signal to another T-NCU 3 or terminates communication depending on the content of the command. As a result, it is possible to continuously communicate with another communication terminal 1 existing on the same extension side by omitting the operation before the second dial and performing a connection sequence from the second dial. Goes up.

Next, when a call is transmitted from the T-NCU 3 shown in FIG.
3 is sent. In T-NCU3 , the communication phase
There are cases where the telephone number of the hand (C-NCU 6) is set and cases where the telephone number of the communication destination (C-NCU 6) is received from the communication terminal 1; Date
In accordance with the data, after the off-hook, an identification code indicating the activation from the communication terminal 1 is added to the dial signal, and dialing is performed in a form as shown in FIG. Thus, the PBX 4 can determine that the call is from the communication terminal 1. However, if the telephone 2 is off-hook, the activation signal of the communication terminal 1 is suspended until it is ignored or on-hook.

Thereafter, a call signal is issued to the C-NCU 6 in the same manner as in the normal incoming call sequence of the telephone 2. The C-NCU 6 receiving the call signal is sent to the host computer 7
A start signal is sent to the terminal to go off-hook. By the connection sequence described above, the host computer 7 and the communication terminal 1 are connected with the C-NCU 6 and the T-NCU 3 interposed therebetween, and become communicable. Subsequent operations are the same as in the case of transmission from the C-NCU 6 described above.

Next, a connection sequence when an abnormality occurs will be described. As shown in FIG. 7, when the telephone 2 is used and a call is made from the C-NCU 6 while the telephone line is in use, the PBX 4 checks whether the telephone line is in use and then sets the T-line.
Line busy P indicating that the NCU side line is in use
The B signal is periodically transmitted to the C-NCU 6 to wait for an instruction. When the C-NCU 6 receives the signal, it sends a line busy signal to the host computer 7 and waits for a command from the host computer 7. As a result, the host computer 7 recognizes that the C-NCU 6 cannot be connected to the T-NCU 3 due to the collision between the no-ringing call to the T-NCU 3 and the call from the telephone 2, and sends a command corresponding to this to the C-NCU 3. NCU6
To the PBX 4 via. Even if the call from T-NCU3 collides with the no-ringing call,
Similarly, it can be recognized on the C-NCU 6 side.

Then, the C-NCU 6 takes measures such as making a no-ringing call again after a while, or performing communication using a dedicated line.

When the telephone 2 is not used on the T-NCU 3 side when an outgoing call is made from the C-NCU 6, but an abnormality occurs due to noise or the like, as shown in FIG.
X4 does not return a response PB signal even if it sends an activation signal to T-NCU3. At this time, the PBX 4 periodically sends a no-response PB signal indicating that there is no response to the C-NCU 6, and waits for an instruction. On the other hand, upon receiving the C-NCU 6, the C-NCU 6 sends a no-response signal indicating the content to the host computer 7, and then waits for a command from the host computer 7. Therefore, the host computer 7 informs the PBX that the T-NCU 3 has failed.
4 can be recognized by the PB signal. Then, it investigates the cause of the abnormality, issues an instruction to check the T-NCU 3, and performs a recovery operation by remote control.

The activation signal from the PBX 4 to the T-NCU 3 is a PB signal (hereinafter, referred to as NRS and NRS) of the selection number of the T-NCU 3 to be activated after inverting the polarity of the line (hereinafter referred to as pole reversal). ) Is transmitted.

Therefore, the T-NCU 3
Can control the line depending on whether there is a pre-linger (a ringer of a different cycle may be sent before a ringer of a normal cycle, and this is called a pre-ringer) or NRS after the reciprocity. Therefore, if the normal line is disconnected from the telephone 2, the tingling of the telephone 2 due to the reciprocity is prevented, and it is possible to enter the communication mode (no ringing communication) without ringing the telephone 2. FIG. 9 shows the line switching operation. In other words, the T-NCU 3 detects the presence or absence of a pre-ringer signal when a reciprocation is performed, and connects the line to the telephone 2 if the pre-ringer signal is present. If there is no pre-ringer signal, the presence or absence of NRS is detected, and if there is NRS, the line is set to the communication mode and no ringing communication is performed.

Here, if it is desired to provide a pre-ringer service for generating a short ringing tone before a normal ringing tone to the telephone 2 or the like in which the T-NCU 3 is interposed, the T-NCU 3 operates as described above. As shown in FIG.
The pre-linger is absorbed while the line is switched in the NCU 3, and the pre-linger does not appear on the telephone 2 or the like.
Therefore, in the PBX 4, as shown in FIG.
Sending the pre-ringer signal twice at regular intervals, taking into account the line switching time to the other (double pre-ringer)
As a result, the first prelinger signal is absorbed during the line connection switching, but the second prelinger signal is not absorbed and reaches the telephone 2, a preliminary ringing sound is generated by the prelinger signal, and the preringing service is provided. Becomes possible.

In the PBX 4, the telephone 2 on the extension side is used.
It is possible to set whether or not to provide a pre-ringing service for the same, etc., and the setting contents are held as system data. Therefore, the setting can be easily changed by changing the setting, and a wide range of services can be provided.

Next, the host computer 7 and the communication terminal 1
The operation when the telephone 2 is hooked off during the communication state will be described with reference to FIG.

The T-NCU 3 always monitors whether the telephone 2 is off-hook. If the telephone 2 is off-hook, it checks whether or not no-ringing communication is being performed. If communication is in progress, a hooking pulse is sent to the PBX 4 and the line is connected to the telephone 2 side.

The PBX 4 that has received the hooking pulse checks whether or not no ringing communication is being performed at this time, and performs an additional function unique to the PBX 4 such as transfer (a transfer function between extensions) when communication is not being performed. During communication, the hooked line is immediately switched to be usable as a normal telephone line, and a dial tone signal is sent to the telephone 2 to perform a normal telephone 2 connection sequence. Thereby, TN
Even when the CU 3 is in a no-ringing communication state with the C-NCU 6, the telephone set 2 can be used.

On the other hand, for the C-NCU 6, the PBX 4
Periodically sends a telephone off-hook PB signal indicating that the telephone 2 is off-hook, and waits for an instruction. C-
Upon receiving this signal, the NCU 6 sends a signal to that effect to the host computer 7 and waits for an instruction. Thus, the host computer 7 can easily know that the telephone 2 has been off-hook, even during communication, and can immediately send a signal instructing the next operation.

As described above, when the T-NCU 3 does not normally respond to the call from the center, when the telephone 2 is used after the response, when the T-NCU 3 collides with the call from the terminal, and when the terminal In each of the above cases when there is an error in the PB4 communication between the PBX 4 and the center or the terminal due to noise, etc.
Bidirectional data communication between the various terminals 1 connected to the extension in X4 and the center becomes possible.

Therefore, in a no-ringing communication system via PBX4, C-NC
Both U6 and PBX4 time out and the probability of having to perform on-hook operation is dramatically reduced,
Operation as a smooth data communication system becomes possible.
Also, even during communication between the C-NCU 6 and the communication terminal 1,
The use of the telephone 2 or the like connected to the T-NCU 3 can be switched, so that the telephone 2 can be used at any time. Moreover, C-NCU6 and T-NCU
Even when there is a case where the connection cannot be established between the three, the PBX 4 grasps the state and outputs a PB signal indicating each state to C-
By transmitting to the NCU 6, the C-NCU 6 can grasp the situation, and can cope with each situation to construct a smoother no-ringing communication system.

Here, the T-NC having the above-mentioned features is provided.
Efficient data communication can be performed by using only one U3. However, by connecting a plurality of T-NCUs in series, a wider communication system can be obtained. In this case, as shown in FIG. 13, in each of the T-NCUs 3 _{a to} 3 _n , the connection switching circuit 14 is forcibly set by the line switching switch 19 to a state in which the line side and the telephone side are connected. Only the T-NCU 3 _n is set in a state where the connection switching circuit 14 is disconnected.

Here, the T-NCUs 3 _{a to} 3 _n always detect reciprocity, prelinger, and NRS in the primary circuit as shown in FIG. 2 even if the line side and the telephone side are forcibly connected. , telephone calls be one other than the end of the T-NCU 3 _n can determine the status of the connection switching circuit 14 also T-NCU3 _a ~3 _n is monitoring. Therefore, if there is a telephone call, the T-NCU3 _a ~3 _n is found to be a telephone call, T-NCU3 _a ~ other than the last T-NCU 3 _n the state of the connection switching circuit 14
3 _n-1 knows that the telephone 2 is not connected to itself, and does nothing operatively. On the other hand, the last T-NCU
3 _n because knows that the phone 2 is connected to the own, it is possible to perform the operation for the telephone call.

Even when a plurality of T-NCUs are connected, each T-NCU can be identified by changing the NRS. Therefore, by selecting and connecting a specific one of them, the T-NCU can be connected. No ringing communication can be performed without any difference from the case of one NCU.

It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that many modifications and changes can be made to the above-described embodiment within the scope of the present invention. For example, P
When transmitting the disconnection PB signal from the BX to the C-NCU,
Instead of transmitting until there is a response, a time limit may be provided and the transmission may be stopped if time is available. Also, in FIG. 12, when the telephone is off-hook during communication between the C-NCU and the T-NCU, the line is switched to the telephone and the data of the communication terminal is stored in the PBX at the same time. C-NCU saves the stored data
Or the line may be automatically restored after the telephone goes on-hook.

[0046]

As is apparent from the above description, according to the present invention, in a no-ringing communication system via a PBX, when a terminal does not normally respond to a call from a center, a telephone is set during data communication. When used, in the case of a collision with a call from the terminal side, and in a call from the terminal side, there was an error in the communication by the PB signal between the PBX and the center side or the terminal side due to noise or the like. Even in such cases, bidirectional data communication can be performed between the terminal connected to the extension in the PBX and the center.

As a result, both the C-NCU and the PBX time out due to the influence of noise and the like, and the probability of having to perform the on-hook operation is drastically reduced, thereby enabling a smooth operation of the data communication system. Further, even during communication between the center and the terminal, the use of a telephone or the like connected to the T-NCU can be switched, so that the telephone can be used at any time.

Further, even when there is a case where the connection between the C-NCU and the T-NCU cannot be established, the PBX can grasp the state and transmit a PB signal indicating each state to the C-NCU. As a result, the C-NCU can grasp the situation, and the center can deal with each situation, and a more smooth data communication system can be constructed.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a data communication system according to an embodiment of the present invention.

FIG. 2 is a block diagram of a network control device.

FIG. 3 is a connection sequence diagram at the time of center transmission.

FIG. 4 is a diagram showing operation timing of a PBX transmission signal;

FIG. 5 is a connection sequence diagram at the time of terminal transmission.

FIG. 6 is a diagram of dial transmission by T-NCU.

FIG. 7 is a connection sequence diagram when a line is used.

FIG. 8 is a connection sequence diagram at the time of abnormality.

FIG. 9 is a flowchart of line switching of a T-NCU.

FIG. 10 is a waveform diagram of a call signal including a pre-ringer to a telephone.

FIG. 11 is a waveform diagram of a call signal including a double pre-ringer to a telephone.

FIG. 12 is a connection sequence diagram when the telephone is off-hook during communication.

FIG. 13 is a diagram showing a connection state when a plurality of T-NCUs are used.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Communication terminal 2 Telephone 3 Terminal network controller 4 Private branch exchange 5 General telephone line network 6 Center network controller 7 Host computer

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Norihiro Yamanaka 22-22 Nagaikecho, Abeno-ku, Osaka, Osaka Inside Sharp Corporation (72) Inventor Yukiya Higuchi 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Sharp Inside (72) Inventor Koji Akiyama 2-5-7 Koishikawa, Bunkyo-ku, Tokyo Meisei Electric Co., Ltd. (72) Inventor Eiji Okuda 2-57 Koishikawa, Bunkyo-ku, Tokyo Meisei Electric Co., Ltd. (72) Inventor Masanobu Tada 2-57-7 Koishikawa, Bunkyo-ku, Tokyo Meisei Electric Co., Ltd. (58) Field surveyed (Int. Cl. ⁷ , DB name) H04M 11/00-11/10

Claims (15)

(57) [Claims] 1. One or more terminal network controllers connected to a terminal device and a telephone, a private branch exchange connected to the terminal network controller via an extension, and a private branch exchange connected to the private branch exchange via a telephone line. A center network controller connected to the terminal network controller connected to the extension specified by the calling side, and performs a no-ringing call to the terminal network controller, and the center network controller and the terminal network controller The private branch exchange transmits a PB signal indicating on-hook to the center network control device when the terminal network control device that has been called for no ringing goes on-hook after responding. And transmitting the PB signal periodically until there is a response signal from the center network control device. 2. The data communication system according to claim 1, wherein when the center network controller receives a PB signal periodically transmitted from the private branch exchange, the center network controller transmits the PB signal of the private branch exchange. A data communication system, wherein a response signal is transmitted to the private branch exchange in a sleep state. 3. One or more terminal network controllers to which terminal equipment and telephones are connected, a private branch exchange connected to the terminal network controller via an extension, and a telephone line to the private branch exchange. A center network controller connected to the terminal network controller connected to the extension specified by the calling side, and performs a no-ringing call to the terminal network controller, and the center network controller and the terminal network controller In the data communication system for performing data communication between the terminal network control device and the terminal network control device, a call is initiated by a dial operation, and after performing data communication between the terminal network control device and the center network control device, the terminal network When the control device goes on-hook, the private branch exchange returns to P
A data communication system comprising: transmitting a B signal to the center network control device; and periodically transmitting the PB signal until a response signal is received from the center network control device. 4. One or more terminal network controllers connected to terminal equipment and a telephone, a private branch exchange connected to the terminal network controller via an extension, and a private branch exchange connected to the private branch exchange via a telephone line. A center network controller connected to the terminal network controller connected to the extension specified by the calling side, and performs a no-ringing call to the terminal network controller, and the center network controller and the terminal network controller A data communication system for performing data communication between the terminal network control device and the private branch exchange that are called by the center network control device in response to a call from the center network control device.
When but it can not be connected, above constituting the exchange data communication system and transmitting a PB signal indicating a non connection state to said center network controller. 5. One or more terminal network controllers connected to a terminal device and a telephone, a private branch exchange connected to the terminal network controller via an extension, and a telephone line connected to the private branch exchange. A center network controller connected to the terminal network controller connected to the extension specified by the calling side, and performs a no-ringing call to the terminal network controller, and the center network controller and the terminal network controller A data communication system for performing data communication between the terminal network controller and the terminal network controller when a call is originated by a dial operation of the terminal network controller. A data communication system characterized by adding an identification signal indicating that 6. One or more terminal network controllers connected to a terminal device and a telephone, a private branch exchange connected to the terminal network controller via an extension, and a private branch exchange connected to the private branch exchange via a telephone line. A center network controller connected to the terminal network controller connected to the extension specified by the calling side, and performs a no-ringing call to the terminal network controller, and the center network controller and the terminal network controller In the data communication system for performing data communication between the terminal network control device and the terminal network control device, the terminal network control device monitors whether or not the telephone is off-hook. When the terminal network controller detects the off-hook of the telephone, the terminal network controller transmits a signal indicating that the telephone has gone off-hook to the private branch exchange. Data communication system to be. 7. The data communication system according to claim 6, wherein the private branch exchange periodically transmits a PB signal indicating that the telephone set has gone off-hook to the center network controller until a response signal is received from the center network controller. A data communication system, comprising: 8. The data communication system according to claim 6, wherein the terminal network control device connects a telephone line to the off-hook telephone, and the private branch exchange switches the telephone line to a usable state. Data communication system. 9. A data communication system according to claim 5, when there is outgoing call from the terminal network controller, private branch exchange detects this call, above constituting the exchange from a terminal device to the center network controller A data communication system for transmitting a signal indicating that the call is a call. 10. A device to which a terminal device and a telephone are connected.
One or more terminal network controllers, a private branch exchange connected to the terminal network controller via an extension, and a center network controller connected to the private branch exchange via a telephone line, and A data communication system that performs a no-ringing call to the terminal network control device connected to the extension designated by the side and performs data communication between the center network control device and the terminal network control device, After performing the polarity reversal of the telephone line between the private branch exchange and the terminal network controller to be called, the private branch exchange transmits a pre-ringer signal to the terminal network controller before a normal ringer signal, and The control device detects the presence or absence of the pre-ringer signal, and connects the telephone line to the telephone when detecting the pre-ringer signal. Tem. 11. A terminal to which a terminal device and a telephone are connected.
One or more terminal network controllers, a private branch exchange connected to the terminal network controller via an extension, and a center network controller connected to the private branch exchange via a telephone line, and A data communication system that performs a no-ringing call to the terminal network control device connected to the extension designated by the side and performs data communication between the center network control device and the terminal network control device, After performing the polarity reversal of the telephone line between the private branch exchange and the terminal network controller to be called, the private branch exchange transmits a plurality of pre-ringer signals to the terminal network controller before a normal ringer signal, In the terminal network control device, the presence or absence of the pre-ringer signal is detected, and when the pre-ringer signal is detected, the telephone line is connected to the telephone, and the telephone is normally connected to the telephone. A data communication system characterized in that a preliminary ringing tone is generated before a ringing tone. 12. The data communication system according to claim 10, wherein the private branch exchange performs setting switching as to whether or not to transmit a prelinger signal to a terminal network control device. 13. A device to which a terminal device and a telephone are connected.
One or more terminal network controllers, a private branch exchange connected to the terminal network controller via an extension, and a center network controller connected to the private branch exchange via a telephone line, and A data communication system that performs a no-ringing call to the terminal network control device connected to the extension designated by the side and performs data communication between the center network control device and the terminal network control device, A transmission signal when calling from the center network control device to the private branch exchange includes data indicating an incoming call to the terminal network control device, and the private branch exchange includes, in the transmission signal,
Whether it is a general incoming call based on the data included
Alternatively , the data communication system is characterized in that it is determined whether or not the call is received by the terminal network control device . 14. A plurality of terminal network controllers connected to terminal equipment and a telephone, a private branch exchange connected to the terminal network controller via an extension, and a private branch exchange connected to the private branch exchange via a telephone line. A center network control device, and performs a no-ringing call to the terminal network control device connected to the extension designated by the calling side, so that a communication between the center network control device and the terminal network control device is performed. In the data communication system for performing data communication, the terminal network controllers are connected in series, and the terminal network controllers other than the terminal network controller located on the rearmost telephone side are connected to the private branch exchange. A data communication system, wherein a circuit connecting the terminal and the telephone is connected, and the circuit can be disconnected and disconnected in the last terminal network control device. 15. The method of claim 1 to 14 data communication system according, center network controller and the terminal network controller, using the PB signal as a response signal to the private branch exchange, said center network controller and the terminal network controller A data communication system using a signal different from the PB signal in communication with the data communication system.