JPH03107268A - Connection system between center equipment and terminal equipment by public telephone network - Google Patents

Abstract

PURPOSE:To prevent occurrence of a wrong dial call by dialing a center equipment after the detection of off-hook of a telephone set, detection of an identification signal from a center equipment and detection of line open so as to connect a data terminal equipment to a public telephone network. CONSTITUTION:When the user is absent and a telephone set 6 is not hooked off for a prescribed time or over, a center equipment 1 opens the line when polarity inversion does not take place for a prescribed time after the transmission of a selection signal that is, when a telephone set 6 of a terminal equipment 3 is not hooked off. Then the communication is started after awaiting the call from a data terminal equipment 5. When a call signal is not stopped for a prescribed time (t1) or longer after the detection of the call signal at a call signal detection circuit 8 in a network controller 4 of the terminal equipment 3, a control line 12 informs the presence of a call from the equipment 1 to the terminal equipment 5 after the stop of the call signal and controls a relay to switch the relay contact 11 to the position of the terminal equipment 5 and to connect the terminal equipment 5 to a public telephone network 2. The equipment 5 makes communication with the equipment 1.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a connection method between a center device and a terminal device via a public telephone network, and particularly relates to a method for connecting a center device and a terminal device via a public telephone network, and particularly to a method for connecting a telephone and a data terminal device that are shared by the terminal device by switching one line. This relates to the connection method when equipped with the following.

[Prior art]

Conventionally, as a technology in this kind of field, Japanese Patent Application Laid-Open No. 58-532
There was one disclosed in Publication No. 63.

This technology is a data transmission device that transmits data using a general subscriber telephone line, and includes a polarity determination circuit that determines the polarity of the direct current of the telephone line, a time limit circuit that is activated by the reversal detection output of this polarity determination circuit, and a telephone An off-hook detection circuit detects off-hook of the telephone and a meter sensor etc. when the off-hook state of the telephone is continuously detected from the output of the off-hook detection circuit until a certain period of time elapses after the output from the time limit circuit is sent. A switch circuit is connected to the telephone line and is controlled to connect the code transmitter (data terminal equipment) to the telephone line.

In this data transmission device, when a call is made from the center equipment, the terminal equipment determines that the call is from the center equipment and disconnects the line if the telephone on the terminal side does not go off-hook within a certain period of time (time set by the time limit circuit). It is designed to automatically receive a call and start communication.

[Problem to be solved by the invention]

However, in the data transmission device described above, if a non-telephone terminal device such as an answering machine or a fax machine is connected as the telephone of the terminal device, the condition is that the terminal device determines that the center device is calling and seizes the line. The condition of "not going off-hook for a certain period of time" may not hold true.

As a countermeasure against this, the center equipment is equipped with a transmission means that sends out an identification signal when it detects the polarity reversal of the line within a certain period of time after sending the selection signal, and the terminal equipment transmits an identification signal when the calling signal does not stop for a certain period of time or when the calling signal remains constant. A possible method is to provide a means for connecting the data terminal equipment of the terminal device to the public i-telephone network when the off-hook of the telephone is detected and an identification signal from the center device is detected before the telephone is stopped within a certain period of time.

However, even with this method, when the carrier signal of the PB double-signal modem is used as the identification signal from the center equipment, the terminal equipment may mistakenly receive a call to an answering machine or FAX, and the data terminal equipment may be connected to the public telephone network. There was a problem with connecting to.

The present invention has been developed in view of the above-mentioned points, and eliminates the above-mentioned problems, and prevents calls received from a non-telephone terminal device such as an answering machine or a fax machine of a terminal device from being mistakenly received by the terminal device.
An object of the present invention is to provide a method for connecting a center device and a terminal device via a public telephone network without connecting data terminal equipment to the public telephone network.

[Means to solve the problem]

In order to solve the above problems, the present invention provides that if a center device detects a line polarity reversal within a certain period of time after sending a selection signal, it sends out an identification signal and releases the line, or does not detect a line polarity reversal for more than a certain period of time. and the means to open the line,
When the terminal device detects the telephone off-hook when the ringing signal does not stop for a certain period of time or after the ringing signal stops or before the ringing signal stops within a certain period of time, and when it detects the identification signal from the center device, it detects the line release. The present invention is characterized in that it has means for making a call to the rear center equipment and connecting the data terminal equipment to the public telephone network.

[Effect]

By connecting the center device and the terminal device as described above, the terminal device can detect the off-hook of the telephone when the ringing signal does not stop for a certain period of time, after the ringing signal stops, or before the ringing signal stops within a certain period of time. In addition, when an identification signal from the center device is detected, the center device calls the center device after detecting a line open and connects the data terminal device to the public telephone network.
Even if the carrier signal of the PB double-signal modem is used as the identification signal from the center device, the data terminal device 5 may be mistakenly received as a call received from a non-telephone terminal device such as an answering machine or a fax machine, and the data terminal device 5 is sent to the public telephone network 2. I can't connect to it.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is a block diagram showing the system configuration of a communication device to which the connection method of the present invention is applied. As shown in the figure, the communication device includes a center device 1, a terminal device 3, and a public telephone 1q2 that connects the center device 1 and the terminal device 3.

The center device 1 sends an identification signal and releases the line if the polarity of the line is reversed within a certain period of time after sending the selection signal (dial signal), and if it does not detect the polarity reversal of the line for more than a certain period of time after sending the selection signal. This configuration includes a transmitter 13 that opens the line.

The terminal device 3 has a configuration including a telephone 6, a data terminal device 5, and a network control device 4.

The network control device 4 of the terminal device 3 detects the hook state monitoring circuit 7 for detecting the hung state of the telephone 6, the ringing signal detection circuit 8 for detecting the ringing signal, and the identification signal from the transmitting unit 13 of the center device 1. An identification signal detection circuit 9, a current detector 10 that detects the hook state of the telephone 6 and a ringing signal, and a telephone 6
and a relay contact 11 for switching between the data terminal equipment 5 and the data terminal equipment 5, an interface signal line 14 between the control circuit 12 of the network control device 4 and the data terminal equipment 5, the hook state monitoring circuit 7, the calling signal detection circuit 8, and the identification signal detection circuit. 9 and a control circuit 12 that receives signals from the data terminal equipment 5 and controls a relay (not shown) having the relay contact 11.

Next, we will explain the operation of the above configuration when no one is present at the installation location of the terminal device 3 and the telephone 6 is not off-hook for a certain period of time.
The operation will be explained separately for the case where the telephone 6 goes off-hook within a certain period of time.

(1) When the telephone 6 of the terminal device 3 is not off-hook for a certain period of time or more due to absence of a person If the polarity of the line is not reversed within a certain period of time (t,) after sending the selection signal, the center device 1 detects that the telephone 6 of the terminal device 3 If not off-hook, release the line. After that, it waits for a call from the data terminal device 5 and starts communication.

When the network control device 4 of the terminal device 3 detects the paging signal in the paging signal detection circuit 8 and the paging signal does not stop for a certain period of time (tl), the control circuit 12 sends the data terminal device 5 a center signal after the paging signal stops. Notification is made that there is a call from the device 1, and the relay is controlled to switch the relay contact 11 to the data terminal device 5 side and connect the data terminal device 5 to the public telephone network 2. The data terminal device 5 makes a call to the center device 1 .

(2) When the telephone 6 of the terminal device 3 is off-hook within a certain period of time When the center device 1 detects a polarity reversal within a certain period of time (t,) after sending the selection signal, that is, when the telephone 6 of the terminal device 3
When the line goes off-hook, the transmitter 13 sends out an identification signal and releases the line. After that, it waits for a call from the data terminal device 5 and starts communication.

After the calling signal detection circuit 8 of the network control device 4 of the terminal device 3 detects the calling signal, the telephone 6
When the off-footer is detected and the identification signal detection circuit 9 detects the identification signal from the center device 1, the center device 1 releases the line, and then the control circuit 12 instructs the data terminal device 5 to receive a call from the center device 1. At the same time, it controls the relay and connects the relay contact 11 to the data terminal device 5.
The switching data terminal device 5 is connected to the public 1-channel network 2. The data terminal device 5 makes a call to the center device 1 . Communication with the center device 1 is started.

FIG. 2 is a flowchart showing the operation of the transmitter 13 of the center device 1. As shown in FIG. As shown in the figure, first, the center device 1 closes the line (step 101) and sends out a selection signal (step 102).

Next, it is determined whether a certain period of time (1+) has elapsed or not (Step 03), and if No, then it is determined whether the polarity of the telephone 6 of the terminal device 3 has been reversed or not (Step 104).
If the answer is No, the process returns to step 103, and if the answer is yes, an identification signal is sent (step 105), and then the line is opened (step 106). Further, in the case of YES in step 103, that is, for a certain period of time (t
, ) have elapsed, the line is also released (step 106
).

FIG. 3 is a flowchart showing the operation of the network control device 4 of the terminal device 3. As shown in the figure, the control circuit 12 of the network control device 4 determines whether the paging signal detection circuit 8 has detected a paging signal (step 110), and if YES, whether a certain period of time (t,) has elapsed or not. If NO, it is determined in step 111), and if NO, it is determined in step 1 whether the hook state monitoring circuit 7 has detected off-hook of the telephone 6.
12), if No, return to step 111 and select YE.
If S, it is determined whether the identification signal detection circuit 9 has detected an identification signal (step 113); if No, the process returns to step 110; if YES, it is determined whether the telephone 6 is on-hook or not. 114), if YES, the data terminal device 5 is notified that there is a call from the center device 1 (step 115). Also, if YES in step 111, that is, for a fixed period of time (1+
) has elapsed, it is determined how to stop the call (step 116), and if YES, the process moves to step 115).

〔Effect of the invention〕

As explained above, according to the present invention, even when a non-telephone terminal such as an answering machine or a fax machine is connected as a telephone to a terminal device, and a carrier signal of an FB double signal modem is adopted as an identification signal from the center device, Answering machine or F
An excellent effect is obtained in that the problem that a call received from a non-telephone terminal such as AX is mistakenly received by the terminal device as a call received by a data terminal device does not occur.

[Brief explanation of drawings]

1 is a block diagram showing the system configuration of a communication device to which the connection method of the present invention is applied, FIG. 2 is a flowchart showing the operation of the transmitter of the center device 1, and FIG. 3 is a network control device 4 of the terminal device 3. 3 is a flowchart showing the operation of FIG. In the figure, 1... center device, 2... public telephone network,
3...Terminal device, 4...Network control device, 5...
・Data terminal equipment, 6...Telephone, 7...Hook status as parent circuit, 8...Call signal detection circuit, 9...
...Identification signal detection circuit, 10...Current detector, 11
...Relay contact, 12...Control circuit, 13...
... Transmission section, 14... Interface signal line.

Claims (1)

[Scope of Claims] A device that performs communication by connecting a center device and a terminal device via a public telephone network, wherein the terminal device switches one line to share a telephone and a data terminal device. In the connection method between the center device and the terminal device, in which communication is performed between the center device and the terminal device, the center device sends out an identification signal when it detects a polarity reversal of the line within a certain period of time after sending out the selection signal. The terminal device has means for opening the line when the ringing signal does not stop for a certain period of time, or after the ringing signal stops, or when the ringing signal does not stop for a certain period of time. The present invention further includes means for detecting off-hook of the telephone before it is stopped within a few seconds and detecting the identification signal from the center equipment, calling the center equipment after detecting the line opening and connecting the data terminal equipment to the public telephone network. The feature is the connection method between the center equipment and the terminal equipment via the public telephone network.