JPH02248136A - Modem pool connection system - Google Patents

Abstract

PURPOSE:To attain data communication even to an opposite terminal equipment without the return of a responding signal by providing a tone detection circuit discriminating the presence of a predetermined tone to a modem interface trunk interfacing the MODEM and instructing the result of detection of the presence to a central controller. CONSTITUTION:When a data terminal equipment 7 makes a call to a data terminal equipment 16, a data terminal interface equipment 8 detects the call and informs it to a central controller 10. The controller 10 operates a time division switch 9 connected thereto to send the data signal of the equipment pigment 7 to an analog line trunk 11 from a MODEM 13 via a MODEM interface trunk 12 and arrived at a MODEM 15 via a public network 14. In this case, a tone detection circuit 3 discriminates the presence of an answer tone sent from the MODEM 15 and informs it to the controller 10 via the controller 4 when the tone is present. Thus, the data communication between the MODEMs 15 and 13 is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for connecting modems pooled as common devices in a stored program exchange digital electronic exchange.

(Prior Art) In conventional digital electronic exchanges, when performing data communication between stations using analog lines, the entire configuration as shown in FIG. 2 has been adopted.

In FIG. 2, since the modem 13 is used as a common device in the switching system, the modem interface trunk 1
2 is housed in the exchange.

The data terminal device 7 and the modem 13 connected to the data terminal device 7 and the data terminal interface device 8 are connected to a time division switch 9 and a modem interface trunk 12.
connected via. The modem interface trunk 12 performs digital/analog conversion, and again,
Analog line trunk 11 via time division switch 9
connected to. Analog line trunk 11 is public M41
4, and is connected to the opposite modem 15.

The communication path between the data terminal devices 7 and 16 is thus connected, and data communication becomes possible.

(Problem to be Solved by the Invention) Now, in this conventional modem pool connection method, if the data terminal device 16 that is the destination of the data terminal device 7 is a line for incoming call charges, etc., the data terminal device 16 responds. Even if this happens, the public network 14 does not send a response signal to the analog line trunk 11.

Therefore, the central controller 10 does not instruct the modem interface trunk 12 to answer since the data terminal device 7 is still calling the data terminal device 16i.
In this case, the E)L (terminal ready signal) for the modem 13 is not fully turned on.

Therefore, there is a problem in that carrier signals are not transmitted and received between the modem 15 and the modem 13, and data communication may become impossible.

An object of the present invention is to solve the above-mentioned problems, and to provide a complete modem pool connection system that enables full data communication even when the other party's data terminal equipment is a line that charges for incoming calls.

(Means for Solving the Problems) In order to achieve the above object, the modem pool connection method according to the present invention centrally installs a large number of modems in a digital electronic exchange that adopts the stored program exchange method, and connects the modems to a modem interface trunk. In a modem pool connection method that enables common use of the modem by each data terminal device accommodated in the time division switch by connecting to the time division switch via the modem interface trunk, a tone detection circuit for detecting the presence or absence of a tone; and a control means for instructing a central control unit that controls switching of the digital electronic exchanger to detect the tone when the tone is detected. It is.

According to the above configuration, the central control unit can issue an instruction of response Wb to the modem interface trunk even if the other party's terminal uses the incoming call charging method, and the central control unit can issue an instruction called "Response Wb" to the modem interface trunk, so that the modem can receive an ER''
ON” signal can be sent.

(Example) Hereinafter, the present invention will be explained in more detail with reference to all the drawings.

FIG. 1 is a block diagram showing an embodiment of a modem interface trunk to which the method of the present invention is applied.

This trunk has a data terminal device interface section for the modem and an analog signal interface section for data modulated by the modem, and can handle two channels: a data channel and a voice channel.

The data signal interface circuit 5 transmits the data signal of the terminal sent from the data channel to the modem which performs all speed conversion so that it becomes the same as the data transmission speed of the terminal.

A modem modulates the transmitted data signal into an analog signal. The analog signal modulated by the modem is converted from 2-wire to 4-wire by the hybrid circuit 2, then digitized by the codec 1 and sent to the audio channel. Further, various control signals sent and received to and from the modem are controlled by the control device 4 throughout the p control signal interface circuit 6. The tone detection circuit 3 is a time division switch 9
This is to notify the control device 4 whether or not there is an answer tone in the signal sent to the modem.

Next, a case where the above-mentioned modem interface trunk is accommodated in an all-digital electronic exchange will be explained with reference to FIGS. 1 and 2.

When the data terminal device 7 makes a call to the data terminal device 16, the data terminal interface device 8 detects the call and notifies the central control device 10. Central control unit lO
In the time division switch 9, as shown in FIG.
It is connected to analog line trunk 11 via . The analog line trunk 11 is connected to the public network 1 by normal outgoing operation.
The call arrives at modem 15 via 4. Data terminal device 16
responds and sets ER, ON to modem 15.

Here, it is assumed that the number of the data terminal device 16 is such a number that no response signal is returned to the analog line trunk 11 from the public network 14 due to incoming call charges, etc.

Even if the data terminal device 16 responds, no response signal is sent to the analog line trunk 11, and the analog line trunk 11
does not notify the central controller 10 that there is a response signal. To be sure of this, the central control unit 10 instructs the modem interface trunk 2 to respond.
and cannot enable data communication.

However, the tone detection circuit 3 determines the presence/absence of an answer tone sent from the modem 15 based on the response from the data terminal device 16, and if the answer tone is present, it is sent to the central control device 10 via the control device 4. It is configured to notify you of this. Therefore, when the data terminal device 16 responds, an answer tone is sent from the modem 15, and the answer tone is sent to the public network 14, analog line trunk 11, and time division switch 9.
When the answer tone reaches the modem 13 via the modem interface trunk 12, the tone detection circuit 3 in the modem interface trunk 12 detects all the answer tones, so an instruction indicating the presence of an answer tone is sent via the control device 4. and sent to the central controller 10. In response to this instruction, the central controller 10 issues an indication to the modem interface trunk 12 that there is a response.

The modem interface trunk 12 sends an ER"ON" signal to the modem 13 in response to this response indication. Therefore, carrier signals are exchanged between modem 15 and modem 13, and data communication becomes 0T.

(Effects of the Invention) As described above, the present invention provides a tone detection circuit that determines the presence/absence of a predetermined tone in the modem interface trunk that interfaces with all modems, and when all tones are detected, Since the central control unit is configured to instruct the central control unit to do so, it is effective in that all data communication can be performed using the modem pool function even with a partner terminal device that does not send back a response signal.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a modem interface trunk to which a modem pool connection system according to the present invention is applied, and FIG. 2 is a diagram showing a relay system for data communication of a data terminal device housed in a digital electronic exchange. 1... POM codec (P(iM) 2... Hybrid circuit (HYH) 3... Tone detection circuit (Tl) ET) 4... Control device (PM) 5... Data signal interface circuit ( I)8I)6
...Control signal interface circuit (O8I) 7...
Data terminal equipment (A) (DT E (A)) 8...
・Data terminal interface device (DM) 9...Time division switch (TSW) 10...Central control unit (00) 11...Analog line trunk (COT) 12...
Modem interface trunk (Ml) T) 13...
Modem (A) (MI) M (A) ) 14...Public network (PSTN) 15...Modem (B) (MDM (B)) 16...
・Data terminal equipment (L) TE (B)) Patent applicant: NEC Corporation

Claims (1)

[Claims] For a digital electronic switching system that adopts the stored program exchange method, a large number of modems are centrally installed, and the modems are connected to a time division switch via a modem interface trunk, so that each data terminal device accommodated in the time division switch can be In the modem pool connection method that enables common use of the modem, the modem interface trunk includes a tone detection circuit that detects the presence or absence of a predetermined tone, and a tone detection circuit that detects the presence of a predetermined tone; A modem pool connection method characterized in that a central control device that controls exchange control is provided with a control means for giving an instruction to detect a tone.