JPS6367849A - Data transmission system - Google Patents

Abstract

PURPOSE:To facilitate the connection of a modem by incorporating a modulating and demodulating circuit and an inter-modem training circuit in a modem pool trunk. CONSTITUTION:The modulating and demodulating circuit 7 and inter-modem training circuit 8 are added to the modem pool trunk 6 on its station side. An switching control means 4 performs training between modems by the inter- modem training circuit 8 at need according to the kind of the modem connected to the opposite station side data terminal and connects the modem pool trunk 6 on its station side to data terminals on its station side and opposite station side when a handshake is made by the training. when the training is not necessary, the modem pool trunk 6 on its station side and the data terminals on its station side and opposite station side are connected by the responding of the data terminals on its station side and opposite station side. The modulating and demodulating circuit 7 performs analog-digital signal conversion on its station side after a data link is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Prior to Industrial Use) The present invention relates to a data terminal connected directly to an electronic private branch exchange having a data transmission function, and a data terminal connected to the electronic private branch exchange through a public switched network. The present invention relates to a data transmission method configured to mutually transmit data between a side data terminal and a side data terminal.

(Prior Art) Conventionally, in this type of data transmission method, an independently installed modem is connected to a modem pool trunk provided as an external device, and the modem pool trunk is used to connect the R8-282C, the NCU, and the line. controlled each interface. FIG. 5 is a block diagram showing an example of a data transmission system according to the prior art. In Fig. 5, 1 is a private branch exchange, 2 is a local data terminal, 3 is a digital line circuit, 4 is an exchange C, PU, and 5 is a central office line trunk.]
] is a modem pool trunk, ]2 is an independently installed modem,
16 is a data adapter.

Next, the prior art will be explained with reference to FIG.

In FIG. 5, an analog port 9 of rank 11 in a modem boot M is connected to a central office line trunk 5, and a digital port 10 of a modem pool trunk 1 is connected to a local data terminal via a digital line circuit 3 and a data adapter 6. 2 are connected to each other. Modulation and demodulation of analog and digital signals is performed by a separately installed modem 2 connected as an external device. The modem pool trunk 11 connects the modem 12 with an R8-282C interface 13, an NCU interface 14,
Controls each signal line with the line interface 15.

The control sequence of these signal lines is
By type 2! ll, and controls the private branch exchange CPU4.

(Problems to be Solved by the Invention) In the conventional data transmission system described above, the independently installed modem is connected to the modem pool trunk as an external device, so the modem is connected to the R3-282C, NCU, A drawback is that a large number of signal lines for each interface with the line must be controlled, making the control complex.

Since the control method for these signal lines differs depending on the modem model, the modem control hardware and
There was a problem in that the software had to be prepared. Furthermore, the modem was expensive and the casing was large, requiring storage space.

The purpose of the present invention is to perform mutual training between the modems as necessary depending on the type of modem connected to the data terminal on the opposite side, establish a connection by establishing a mutual handshake through training, and even if training is not necessary. Specifically, it is an object of the present invention to provide a data transmission system configured to eliminate the above-mentioned drawbacks and to simplify connection of modems by connecting data terminals in response.

(Means for Solving the Problems) The data transmission system according to the present invention is configured to include data terminals on the local side and the opposite side, a modem pool trunk on the local side, and exchange control means. .

The data terminals on the local and opposing sides are for data transmission.

The modem pool trunk on the local side has a modulation/demodulation circuit and an inter-modem training circuit added.

The exchange control means executes training between modems as necessary in an inter-modem training circuit according to the type of modem connected to the data terminal on the other side, and connects the modem to the modem pool trunk on the own side when a handshake is established through training. Connect the data terminals on the local and opposing sides, and if training is not required, the response from the data terminals on the local and opposing sides will connect the modem pool trunk on the local side and the data terminals on the local and opposing sides. It is for connecting.

(Example) Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment that implements a data transmission system according to the present invention.

FIG. 2 is an explanatory diagram showing a connection example when mutual training of modems is required, and FIG. 3 is an explanatory diagram showing a connection when mutual training of modems is required.

1 to 8, ] is a private branch exchange, 2 is a local data terminal, 3 is a digital line circuit, and 4 is an exchange C.
PU, 5 is central office line trunk, 6 is modem pool trunk,
7 is a modulation/demodulation circuit, 8 is an inter-modem training circuit, 16
20 is a data adapter, 20 is a data terminal on the opposite side, 21 is a network control device, 22 is an independently installed modem, 23 is a public switched network, and 24 is a private branch exchange on the opposite side.

First, in FIG. 8(a), a data terminal 20 on the opposite side is connected to a public switched network 23 by a network control device 21 and a modem 22 on the opposite side. The modem 22 on the other side is CCITT
A handshake is established with the other party's modem according to the calling procedure specified in V2S, and then the data terminal 2
R8232CDR (Data aet R
eady) signal to ON1. This notifies the establishment of the data link.

In the following, a case will be described in which the data terminal 2 on the own side makes a call to the station 7 and calls the data terminal 20 on the opposite side.

Upon receiving the call request command from the data terminal 2 on the local side and the keyboard input of the subscriber number of the data terminal on the opposite side, the exchange CPU 4 acquires the central office line trunk 5 and the modem pool trunk 6. Thereafter, the data terminal 20 on the opposing side is called through the public switched network 23. On the opposite side, the network control device 221 and the opposite side modem 22 automatically respond to an incoming call from the public switched network 23 and connect the opposite side modem 22 to the public switched network 23. The local exchange CPU 4 connects the inter-modem training circuit 8 in order to control the calling procedure of the CCIT TV 2S via the central office line trunk 5 in response to the game response. Accordingly, the modem 22 on the other side and the inter-modem training circuit 8 on the own side perform training for checking the modem on the other side and setting communication conditions according to a mutually determined procedure.

Next, as shown in FIG. 3(b), as a result of the training, when a mutual handshake is established between the modem 22 on the opposite side and the inter-modem training circuit 8 on the own side, the modem 22 on the opposite side
R8-282CD for 21d data terminal 2Ω
Turn on the R signal.

This notifies the establishment of the data link.

On the local station side, based on the inter-modem handshake establishment information from the inter-modem training circuit 8, the exchange CPU
4 connects the analog line from the data terminal 20 on the other side to the analog port 9 of the modem pool trunk 6 via the office line trunk 5, and connects the digital line from the data terminal 2 on the own side to the digital port of the modem pool trunk 6. 1
Connect to 0. After setting the data communication path, turn on the R8-282CDR signal of data adapter 6. This is K
Then, the establishment of the data link is communicated to the local data terminal 2.

After the data link is established, the modulation/demodulation circuit on the local station side performs analog/digital signal conversion. The modulation and demodulation method is mainly based on the CCIT TV series recommendations, and by replacing the modulation and demodulation circuit, it is possible to support different modulation and modulation methods.

R8-28 between local data terminal 2 and modem circuit 7
2CIi! The control signals are basically transmitted to each other in a manner equivalent to a cable connection, but the exchange CPU 4 may intervene depending on conditions.

If communication line quality is periodically monitored between modems after the data link is established, it is necessary to keep the inter-modem training circuit 8 connected even after the data link is established. Upon completion of data transmission, detection of restoration of the central office line trunk on the local station side, or detection of transmission disconnection by the modulation/demodulation circuit during full-duplex communication, the converter CPU 4 connects the central office line trunk 5, the modem pool trunk 6, data adapter 1
6 is restored, the data link is disconnected, and data transmission between the data terminals is terminated.

FIG. 3 explains the case where the data terminal 20 on the opposite side is accommodated in the private branch exchange 24 on the opposite side having the same type of modem pool trunk 6. In this case, the exchange machine 24 establishes a mutual data link between the 73rd and
By considering it as υ, there is no need for an inter-modem training circuit.

In addition, in FIGS. 2(a) and 2(b), if the modem 22 on the other side does not perform training such as calling hands, as in the case of a dedicated line modem, the inter-modem training circuit is also used in the modem pool trunk 6. is not necessary, allowing the modem pool trunk 6 to have a much simpler configuration.

FIG. 4 is a block diagram showing an example of application of the data transmission system according to the present invention. In FIG. 4, the same elements as in FIGS. 1 to 8 are numbered the same. On the other hand, 25 is a data terminal accommodating an internal analog line, 26 is an independently installed modem, 27 is a network control device, and 2B is an analog line circuit.

Next, an application example of the present invention will be explained with reference to FIG. 4. FIG. 4 shows an example in which a data terminal 2 accommodating a digital line and a data terminal 25 accommodating an internal analog line are connected using a modem pool trunk 6 for data transmission. According to this data transmission system, data is transmitted not only between stations but also to the data terminal 25 connected to the internal analog line using the network control device 27 and modem 26 using the same control system. be able to.

(Effects of the Invention) As explained above, the present invention incorporates a modulation/demodulation circuit and an inter-modem training circuit in the modem boolean trunk, thereby controlling the NCU interface and line interface that were controlled by the conventional modem boolean trunk. This has the effect that the hardware and control software can be simplified, and that the modem control hardware and software, which have conventionally been associated with each modem model, can be integrated.

Furthermore, compared to the case where conventional independently installed modems are connected, there is also an effect that cost reduction and miniaturization can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the device configuration in the data transmission system of the present invention. FIGS. 2(a) and 2(b) are explanatory diagrams showing an example of mutual training between modems. FIG. 3 is an explanatory diagram showing an example in which modem training is not performed with each other. FIG. 4 is a block diagram showing an example of application of the present invention. FIG. 5 is a block diagram showing an example of the configuration of a conventional system. 1.24...Private branch exchange 2.20.28-Life/Data terminal 3/Φ/Digital line circuit 4...Exchange CPU 5...Central line trunk 8.1]--Modem pool trunk・$Modulation/demodulation circuit 8...=-7'Ml'J training circuit 12.22
．． 26...Independent modem 16...Data adapter 21.27...Network control device 23...Public switching network 28...Analog line circuit 9.10...-Boat

Claims (1)

[Claims] Depending on the type of modem connected to the data terminals on the local side and the opposite side for data transmission, the modem pool trunk on the local side with a modem circuit and inter-modem training circuit added, and the data terminal on the opposite side, and execute mutual training of the modems as necessary in the inter-modem training circuit, and connect the modem pool trunk on the local side and the data terminals on the local side and the opposite side when a handshake is established by the training, If the training is not required, the exchange control means connects the modem pool trunk on the local side and the data terminals on the local side and the opposite side in response to responses from the data terminals on the local side and the opposite side. A data transmission method characterized by being configured as follows.