JPH0752891B2 - Transmittable signal synchronization method for network connection - Google Patents

Description

The present invention relates to a transmittable signal synchronization method in an inter-network connection that takes carrier detection delay into consideration, and an object thereof is to contribute to efficient normal data transmission in inter-network data transmission. And a transmission data terminal device connected to the circuit switching network on the transmission side,
Called side circuit switched network side connected to at least one other communication network that provides a circuit path between the called side circuit switched network and the called side circuit switched network via a call receiving system and a data receiving system including a modem In the complex communication network system for performing data communication with the incoming data terminal device of, after sufficient time has passed to absorb the carrier detection delay in the data receiving system accompanied by the time delay occurring in the establishment of the designated inter-network line path, A first transmission of a transmission enable signal for the first transmission request signal from the originating data terminal device to the originating data terminal device;
And the transmission enable signal for the transmission request signal in the second and subsequent data transmissions is sent to the transmission data terminal device after a lapse of a time sufficient to absorb only the transmission delay in the set inter-network line path. The second means is provided in the data transmission system on the transmission side.

[Industrial application field]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmittable signal synchronization method in inter-network connection that takes into account carrier detection delay when a line path is set through different communication networks.

Recently, data communication and the like are being studied and developed not only within a single communication network, but also in the direction of being performed with other communication networks interposed therebetween. For example, the data terminal device is not only connected to the data terminal device of the other party through the public telephone network to transmit and receive data as in the conventional case, but also the other communication network is provided in addition to the public telephone network. Construction of a communication network in which a line path is formed between the data terminal device and a data terminal device to transmit / receive data is underway. Even in such a case, it is necessary to equip the composite communication network system with the same data transmission capacity as in the case of forming a communication path through the conventional public telephone network.

[Conventional technology]

As described above, when it is desired to perform data communication between the data terminal devices via the composite communication network system, an example of the composite communication network system may have a configuration as shown in FIG. Even in such a complex communication network system, the outgoing data terminal device (hereinafter referred to as outgoing DTE) 50 receives the incoming D
When transmitting and receiving data by forming a line path with the TE52, the dial signal is transmitted from the transmitting DTE50 to the calling public telephone network 54 via the network control unit (hereinafter referred to as NCU) 51 as in the conventional case. (100, 102 in FIG. 5), the originating public telephone network 54 sends a dial signal to the receiving public telephone network 58 via the VAN network 56 (104 in FIG. 5). The called public telephone network 58 calls the called DTE 52 via the called NCU 60 (106 in FIG. 5).

When the incoming DTE 52 sends a response to the call (1 in Fig. 5)
08), the receiving side NCU 60 switches the receiving system to the modem side in preparation for data reception (110 in FIG. 5) and returns a response to the receiving side public telephone network 58 (FIG. 5). 112). Further, when the response is returned to the calling side NCU 51 via the VAN network 56 and the calling side public network 54 (the fifth
(114, 116 in the figure) The originating NCU 53 also switches to the modem side in preparation for data transmission (11 in FIG. 5).
8) and a response is sent to the originating DTE 50 (12 in FIG. 5).
0). Thus, the connection phase ends.

After receiving this response, the originating DTE 50, originating NCU 51, and modem 53
The RS (transmission request) signal and the CS (transmission possible) signal are alternately transmitted and received to and from each other (122 ₁ , 124 ₁ , 126 ₁ , 128 ₁ ; 122 in FIG. 5). ₂ , 124 ₂ , 126 ₂ , 128 ₂ ;
...). At that time, the calling side NCU 51 that has received the RS signal causes the modem 53 to send a carrier signal to the calling side NCU 60 via a line path formed between the calling side NCU 60 and the called DTE 52 (130 _{1 in} FIG. 5). ). When the receiving side NCU 60 detects a carrier wave (hereinafter referred to as a carrier signal), it transfers a CD (carrier detection) signal to the incoming DTE 52 to signal the start of data reception (132 ₁ , 134 ₁ ; 132 ₂ , 134 ₂ ; ・
・ ・).

[Problems to be Solved by the Invention]

If the complex communication network system is configured as described above, during the time required to establish the circuit path in the connection phase, the switching shift to the modem in both the originating and terminating DTE and the originating and terminating D
Disturbances that occur in the line that forms the line path set between TEs are also included, so the carrier signal transmitted from the modem 53 on the calling side under the control of the NCU 51 on the calling side in response to the RS signal from the calling DTE 50. Arrives at the called modem 61 by a time longer than the simple transmission delay after the line path setting is completed. Therefore, the outgoing DTE5
At 0, when the transmission time of the CS signal as a response to the RS signal is set as the time elapsed time in which only the transmission delay is taken into consideration by simply following the conventional method, when the data transmission from the transmission DTE 50 is started, the called modem 61 In this case, the data arrives before the carrier is detected, and the data is truncated. It interferes with the normal transmission of data.

The present invention has been made in view of the above problems, and an object thereof is to provide a transmittable signal synchronization method in inter-network connection that is useful for efficiently performing normal data transmission in inter-network data transmission. To do.

[Means for Solving the Problems]

FIG. 1 shows a block diagram of the principle of the present invention. As shown in this figure, the present invention connects to the originating side circuit switching network 6 through the alternative connection of the receiving side terminal calling system 2 and the data transmitting system 4 including a modem by the alternative connecting means 1. At least 1 for providing a circuit path between the originating data terminal device 8 and the originating side circuit switching network 6 and the receiving side circuit switching network 10.
Composite communication for performing data communication with an incoming data terminal device 18 on the side of the receiving side circuit switching network 10 connected to one other communication network 12 via a call receiving system 14 and a data receiving system 16 including a modem. In the network system, after a lapse of sufficient time to absorb the carrier detection delay in the data receiving system 16 accompanied by the time delay that occurs in the establishment of the designated inter-network line path,
First means 20 for sending a transmission enable signal for the first transmission request signal from the transmission data terminal device 8 to the transmission data terminal device 8, and a transmission enable signal for the transmission request signal in the second and subsequent data transmissions. The data transmission system 4 on the originating side is provided with the second means 22 for sending to the originating data terminal device 8 after a lapse of a time sufficient to absorb only the transmission delay in the set inter-network line path. .

[Work]

A response to a call from a designated incoming data terminal device 18 is sent from the originating data terminal device 8 via the originating side circuit switching network 6, the communication network 12, and the receiving side circuit switching network 10 to each of the networks 10, 1.
When it is received by the called terminal calling system 2 via 2 and 6, the response is sent to the outgoing data terminal device 8. At that time, the connection of the transmission data terminal device 8 to the transmission side circuit switching network 6 is switched to the data transmission system 4. The switching is caused, for example, by the called terminal calling system 2 which has received a response from the called data terminal device 18.

The originating data terminal device 8 that has received the response sends a transmission request signal to the data transmission system 4. If the transmission request signal is the first transmission request signal, a transmission enable signal is transmitted from the first means 20 to the transmission data terminal device 8 at a time when the carrier detection delay is expected and the leading portion of data is not lost. To start data transmission.

If the transmission request signal is the second or later signal, the second
The means (22) sends a transmission enable signal to the transmission data terminal device (8) to transmit data when a sufficient time has passed to absorb only the transmission delay in the set inter-network line path.

By the first means, the accuracy of the transmitted data, that is, the loss of data at the beginning of the data can be prevented, and by the second means, the speed of data transmission can be increased.

〔Example〕

FIG. 2 shows the configuration of a network control unit (NCU) for implementing the present invention in the complex communication network system configuration shown in FIG. Second
In the figure, 20 is a DTE interface, 22 is a central control unit (CPU), 24 is a program memory, 26 is a data memory, 2
8 is an NCU unit and 30 is a DCE interface. The NCU unit 28 has a line state detection unit 40, a dial transmission unit 42, and a switching unit 44. 53 and 61 are modems. Further, 50 and 52 are DTE, and 62 is a public telephone line.

In the central control unit 22, program memory 24 and data memory 26 of FIG. 2, in addition to the conventional longCS function, long-long
CS function 23 is built. Therefore, from the time when the dial signal (connection control signal) is sent from the network control device, the carrier detection delay in the receiving modem 61 due to the time delay occurring in the establishment of the inter-network line path designated by the dial signal is absorbed. First representing a sufficient time value for
The time data of is stored in the data memory 26 together with the second time data for the conventional longCS function, and the program for executing the sequence shown in FIG. 3 is stored in the program memory 24. By executing using the time data in the control unit 22, the long
-The longCS function is implemented in the above components.

2 and 4, the switching unit 44 of the originating NCU 51 corresponds to the alternative switching means of FIG. The central control unit 22, the program memory 24, the data memory 26 and the NCU unit 28 are the first
It corresponds to the called terminal calling system 2 in the figure. The central control unit 22, the program memory 24, the data memory 26 of the transmission side NCU 51, and
The DCE interface 30 and the modem 53 correspond to the data transmission system 4 including the modem shown in FIG. Calling party public telephone network
54, DTE50, called public telephone network 58, VAN network 56, and DTE52
1 corresponds to the originating side circuit switching network 6, the originating data terminal device 8, the receiving side circuit switching network 10, the communication network 12, and the incoming data terminal device 18, respectively. Further, the line state detection unit 40, the central control unit 22, the program memory 24 and the data memory 26 of the receiving side NCU 60 correspond to the call receiving system 14 of FIG. 1, and the receiving side modem 61 and the switching unit 44 of the receiving side NCU 60, The DCE interface 30, the central controller 22, the program memory 24 and the data memory 26 correspond to the data receiving system 16 of FIG.

Then, the program portion of the program memory 24 for processing the above-mentioned first time data in the data memory 26 of the originating NCU 51 and the sequence 122 ₀ , 124 ₀ , 126 ₀ , 128 ₀ in FIG.
Further, the central control unit (CPU) 22 corresponds to the first means 20 in FIG. ₁ , and the above-mentioned second time data in the data memory 26 of the transmission side NCU 51 and the sequence 122 ₁ , 124 ₁ , 126 _{1 in} FIG. , 128 ₁ ;
.. and a central control unit (CPU) 22 correspond to the second means 22 of FIG.

If the NCU is provided with the long-long CS function as described above, it is possible to prevent the data from being truncated when data is transmitted and received through the network. That is, the connection phase in the complex communication network system having the above-mentioned configuration is the same as that described in the section "Prior Art". Calling side NCU5 in connection phase
When a response is returned to 1 (118 in FIG. 3), the switching output 44, which has been connecting the dial transmission unit 42 to the telephone line 62, is changed to the modem 53 by the detection output of the line state detection circuit 40.
To the telephone line 62 (this switching operation is under the conventional method).

Outgoing DTE50 that received the response in the connection phase
Sends the RS signal to the transmitting NCU 51 (122 _{0 in} FIG. 3).

In the transmission side NCU 51, the central control unit (CPU) 22 having received the RS signal via the DTE interface 20 gives the RS signal to the modem 53 via the DCE interface 30 (124 _{0 in} FIG. 3). The modem 53 transmits the carrier signal to the line path formed as described above in the same manner as in the conventional case and (3rd
130 ₀ ), the CS signal is sent to the central control unit 22 via the DCE interface 30 (126 ₀ ). The central control unit 22 sends a call to the originating DTE 50 when the time represented by the first time data has elapsed.
Send the S signal (128 _{0 in} FIG. 3). The originating DTE 50 receiving this CS signal transmits a predetermined amount of data to the terminating DTE 52 via the originating NCU modem 53 as in the conventional case. The data receiving operation on the called side also follows the conventional method (132 ₀ , 134 in FIG. 3).
₀ ).

And RS signal and CS for second and subsequent data transmission
Signal transmission / reception is originating DTE50, originating NCU51 and originating modem
It is done with 53, but this follows the conventional method. At that time, the above-mentioned second time data is used to determine the sending time of the CS signal returned from the calling side NCU 51 to the calling DTE 50. Therefore, the time required to start the data transmission at each time is reduced to the transmission delay time in the set line path as in the conventional case, and the data transmission can be efficiently performed.

Incidentally, in order to return the first CS signal to the transmitting DTE50 in the above embodiment, not the means by the central control unit 22 or the like described above, but a circuit for generating the CS signal when the above time elapses in response to the RS signal from the transmitting DTE50. It goes without saying that the configuration may be replaced with.

〔The invention's effect〕

As described above, according to the present invention, it is possible to prevent loss of the leading portion of data (breakage of data) due to delay in carrier detection after establishment of an inter-network line path for data transmission, and to prevent this data loss. Subsequent data transmission can be done at high speed. These effects can be achieved without providing a ready signal sending circuit on the called side.

[Brief description of drawings]

FIG. 1 is a block diagram of the principle of the present invention, FIG. 2 is an NCU configuration diagram, FIG. 3 is a diagram showing a time chart in the method of the present invention, and FIG. 4 is for returning data through a complex communication network. System configuration diagram, FIG. 5 is a diagram showing a time chart when the conventional method is used. In FIG. 1 and FIG. 2, 1 is an alternative connection means (switching unit 44 of NCU 51 on the calling side), 2 is a call system of the called terminal (central control unit 22 of NCU 51 on the calling side,
Program memory 24, data memory 26 and NCU unit 28), 4 is a data transmission system including a modem (central control unit 22 of transmission side NCU 51, program memory 24, data memory 26 and DCE)
The interface 30 and the modem 53), 6 is the calling side circuit switching network (calling side public telephone network 54), 8 is the calling data terminal device (DTE50), 10 is the receiving side circuit switching network (calling side public telephone network 58), 12 is a communication network (VAN network 56), 14 is a call receiving system (the line state detection unit 40 of the receiving side NCU 60,
Central control unit 22, program memory 24 and data memory 2
6) and 16 are data receiving systems (switching unit 44 of receiving side NCU 60, receiving side modem 61 and DCE interface 30 of receiving side NCU 60, central control unit 22, program memory 24 and data memory 26), and 18 is a receiving data terminal device. (DTE52), 20 is a first means (first of the data memory 26 of the originating NCU 51).
Time data and sequence of FIG. 3 122 ₀ , 124 ₀ , 126 ₀ , 128
The program part of the program memory 24 for processing ₀ , as well as the central control part 22), 22 is the second means (the second part of the data memory 26 of the originating NCU 51).
Time data and sequence of FIG. 3 122 ₁ , 124 ₁ , 126 ₁ , 128
The program part of the program memory 24 for processing ₁ ; ... And the central control part 22).

Claims (1)

[Claims] 1. A calling side circuit switching network (6) through an alternative connection of a receiving side terminal calling system (2) and a data transmitting system (4) including a modem by an alternative connecting means (1). To the at least one other communication network (12) that provides a circuit path between the outgoing data terminal device (8) connected to the outgoing call side circuit switching network (6) and the called side circuit switching network (10). , A composite for performing data communication with an incoming data terminal device (18) on the incoming side circuit switching network (10) side, which is connected via a call receiving system (14) and a data receiving system (16) including a modem. In the communication network system, after a lapse of a time sufficient to absorb the carrier detection delay in the data reception system (16) accompanied by the time delay caused in the establishment of the designated inter-network line path, the first data from the transmission data terminal device (8) Sends a ready signal for the second send request signal The first means (20) for sending to the data terminal device (8) and the transmission enable signal for the transmission request signal in the second and subsequent data transmissions absorbs only the transmission delay in the set inter-network line path. And a second means (22) for sending to the originating data terminal device (8) after a sufficient time has been provided in the originating side data transmission system (4). Synchronous method.