JP3041748B2 - Terminal network controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention connects a telecontrol terminal such as a power meter and a center through a communication line to realize communication between the center and the telecontrol terminal such as automatic meter reading and automatic notification. More particularly, the present invention relates to a terminal network controller that communicates via an analog telephone network.

[0002]

At present, automatic meter reading with the center by connecting a telecontrol device such as an automatic vending machine or a power meter, automatic reporting, there is a terminal network controller for Terekonto b Lumpur system for the remote control. Such a terminal network controller has a transmission rate of 1200 bps and CCITT V.11. Modulation / demodulation means of 23 standards are used. In the communication mode, the terminal network controller does not perform error control to check transmission errors only by modulating and demodulating, but performs error control between the telecontrol terminal and the center, and error control between the center and the terminal network controller. There are modes for performing communication and modes for performing error control communication between the telecontrol terminal and the terminal network control device. As a transmission error check system for exchanging messages between the center and the telecontrol terminal or between the center and the terminal network control device, as disclosed in Japanese Patent Application Laid-Open No. 49-36204, a vertical and horizontal parity bit check system is known. Is used. This method calculates and adds the vertical and horizontal parity bits so that the bits of “1” become even when transmitting a message, and adds the bits of the received value so that the bits of “1” become even when receiving. It is determined whether a transmission error has occurred by checking whether or not the vertical parity bit is added. Therefore, when a bit is garbled such that the number of “1” s in the vertical and horizontal values are both even, it is determined to be normal and no error can be detected.

[0003] In addition to such error control communication means, in other fields other than the telecontrol communication field, for example, V.I. Error control communication means such as a cyclic redundancy check method (CRC type check method) defined in the 41 standard is used.

[0004]

However, such a conventional technique used in the telecontrol communication field is disclosed in CCITT V.15. Since the frequency of bit errors increases because the modulation / demodulation means of the 23 standard is susceptible to line characteristics and noise, the vertical / horizontal parity bit check method has a problem that the probability of error detection increases. Also,
As a means for solving this problem, the probability of error detection can be increased by applying another error control method. However, it is necessary to change all error control communication means of the telecontrol terminal, the terminal network control device, and the center. For this reason, there is also a problem that the device cannot be replaced or changed while operating the telecontrol service.

An object of the present invention is to enable switching between two or more different transmission error control communication means to increase the probability of transmission error detection.

[0006]

In order to achieve the above object, the present invention provides a network control means for connecting to a center by connecting to a telephone line, and transmitting and receiving two or more messages with a center or a telecontrol terminal. A variety of error control communication means performing in different transmission error control, switching means for switching control of transmission error control, relay communication means for performing data communication between the center and the telecontrol terminal via the network control means, There is provided a selecting means for selecting the transmission error control by controlling the switching means by a no ringing selection signal received at the time of the no ringing communication.

[0007]

According to the present invention, the error control communication means is switched by the switching means and the switching means is driven from the center to select the error control communication means, thereby increasing the probability of transmission error detection.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 shows a terminal network control device according to an embodiment of the present invention.
FIG. 3 is a block diagram of a part excluding a selection unit . As shown in the figure, a terminal network control device 1 is connected to a telephone line 6 to connect to a center, a network control unit 2, a parity type communication unit 4 a for performing communication by transmission error control of vertical and horizontal parity check with a center, CCITT V. A CRC-type communication means 4b for communicating with a center by transmission error control of a cyclic redundancy check defined in the standard 41; a switching means 5 for switching between a parity-type communication means 4a and a CRC-type communication means 4b by a switch; 7 is comprised of relay communication means 3 for interrupting communication with.

The switching means 5 operates so that the CRC type communication means 4b operates when the switch is on, and operates the parity type communication means 4a when the switch is off.

The operation of the above configuration will be described.

When the switch is on, the CRC communication means 4b is driven. The center and the terminal network control device 1 are connected by the network control means 2 to start communication, and the communication between the center and the terminal network control device 1 is performed by CRC type communication means 4b for error control communication by cyclic redundancy check. For example, in the case of receiving a message from the center to the terminal network control device 1, CR
The C-type communication means 4a checks the received message by the cyclic redundancy check, and if there is no error, processes the received message, adds the response message to the center with information for the cyclic redundancy check, and transmits the center. If it is a received message from the center to the terminal 7, the CRC type communication means 4b checks the received message by the cyclic redundancy check, and transfers the received message to the terminal 7 by the relay communication means 3 if there is no error. When the switch is off, the parity type communication means 4a is driven. The center and the terminal network control device 1 are connected by the network control means 2 and communication is started, and the communication between the center and the terminal network control device 1 is performed by the parity type communication means 4a for error control communication by vertical and horizontal parity check. For example, in the case of receiving a message from the center to the terminal network control device 1, the parity communication means 4
In step a, the received message is checked by the vertical / horizontal parity check. If there is no error, the received message is processed, and the response message is sent to the center with information for the horizontal / vertical parity check added. If the received message is from the center to the terminal 7, the parity communication unit 4a checks the received message by the vertical / horizontal parity check, and if there is no error, transfers the received message to the terminal 7 by the relay communication unit 3. The transmission of a message from the terminal 7 to the center is performed in the same manner. In this manner, communication is performed by switching the error control communication means 4.

[0013] Then, as shown in FIG. 2, network control unit 2 is one that is adapted to accept a connection by non-ringing call, In addition, if the terminal network controller 1 is connected by non-ringing call from the center, parity type A selection unit 8 is provided which determines which of the communication unit 4a and the CRC type communication unit 4b should be used in accordance with the type of the no ringing selection signal received when the no ringing is received. The selecting means 8 communicates with the center using the parity communication means 4a when the no ringing selection signal is "1", and communicates with the center using the CRC communication means 4b when the no ringing selection signal is "2". It is determined that communication is performed.

The operation of the above configuration will be described.

First, when the network control unit 2 establishes connection with the center by a no-ringing incoming call, the selection unit 8 is activated. When "2" is received as the no ringing selection signal, the selection means 8 considers that communication with the center is to be performed using the CRC communication means 4b, and notifies the switching means 5 to drive the CRC communication means 4b. The switching means 5
Thereafter, the communication with the center is performed by the CRC type communication means 4b. When "1" is received as the no ringing selection signal, the selection means 8 considers that communication with the center is performed using the parity communication means 4a and notifies the switching means 5 to drive the parity communication means 4a. I do. The switching means 5 thereafter communicates with the center by the parity communication means 4
a is used. Thus, the transmission error control communication means 4 can be selected by the no ringing selection signal.

[0016]

As is clear from the above description, the following effects can be obtained according to the terminal network control device of the present invention. (1) Since the error control communication means is switched, it is possible to provide a terminal network control device according to the communication quality of the line or the error control communication means of the center or the terminal. (2) Since the error control communication means is switched according to the designation from the center, even if the terminal for the conventional vertical and horizontal parity check and the terminal for the cyclic redundancy check coexist on the network, the center is connected to the terminal. Since the corresponding communication can be performed, the terminal network control device and the terminal can be sequentially re-installed, so that an effect of facilitating the transfer operation is obtained. (3) Transmission error control communication means using no ringing selection signal
Can be selected.

[Brief description of the drawings]

FIG. 1 is selected in a terminal network control device according to an embodiment of the present invention.
Block diagram of parts excluding means

FIG. 2 is a block diagram of a terminal network control device according to an embodiment of the present invention provided with a selection unit .

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Terminal network control device 2 Network control means 3 Relay communication means 4 Error control communication means 5 Switching means 6 Telephone line 7 Terminal 8 Selection means

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-311067 (JP, A) JP-A-63-262933 (JP, A) JP-A-3-30562 (JP, A) JP-A-3-3 133242 (JP, A) JP-A-3-145366 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04M 11/00-11/10

Claims (1)

(57) [Claims] 1. A network control means for connecting to a center by connecting to a telephone line, a multi-error control communication means for performing transmission and reception of a message with a center or a telecontrol terminal by two or more different transmission error controls, Switching means for switching control, interruption communication means for performing data communication between the center and the telecontrol terminal via the network control means ,
No ringing selection signal received during no ringing communication
Signal to control transmission error control and select transmission error control.
A terminal network control device provided with a selection means .