JPH0556102A - Automatic discrimination device for data length - Google Patents

Abstract

PURPOSE:To supply an automatic data length discrimination device which can automatically discriminate the bit length of data transmitted from a terminal equipment. CONSTITUTION:When a line with the data terminal is established, CPU 201 gives a mode setting signal MD to serial I/O 206. Thus, transmission data given from MODEM 209 is received with the bit length following the signal MD. Since an interruption signal IT is given to CPU 201 when a stop bit is not detected in STX of reception data, CPU 201 discriminates that reception data is not the bit length designated at a present mode. The signal MD which restores the error is outputted, and data is always exactly received/decoded even if the bit length of transmission data is altered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data length automatic discriminating apparatus, and more particularly, it is applied to a data collecting system for collecting data from a terminal device by using a telephone line and automatically determines the bit length of data received from the terminal device. The present invention relates to a device for automatically determining the data length.

[0002]

2. Description of the Related Art Conventionally, information about equipment such as meters and sensors (for example, water meters, gas meters, electric meters, gas leak alarms, fire alarms) provided in homes or other users is called by telephone. There is known a system that uses a line to transmit to a center. In such a system, the center regularly collects information on meters of each user via a telephone line and intensively performs meter reading work for collecting usage charges. In addition, it receives emergency information from gas leak alarms and fire alarms and issues an alarm to detect the occurrence of an abnormality early. Generally, a data collection system using such a telephone line is called a telemetering system.

In the above telemetering system, a terminal network control device is provided for each user, and the information of each meter / sensor is sent to the center side through this terminal network control device. At this time, each meter
The sensor information is sent to the center in each data packet. This data packet contains a plurality of character data, and the bit length of each character data is
It can take different values depending on the model of the meter / sensor. Currently, the bit length of 1 character data is
The standard defines a 5-bit length that does not include a parity bit and a 7-bit length that further includes an even-numbered parity bit.

On the center side, in order to correctly decode the data sent from the terminal network control device of each user, it is necessary to recognize in advance whether the bit length of the sent data is 5 bits or 7 bits. Need to be. Therefore, the computer provided in advance on the center side holds as a management information what kind of meter or sensor is connected to which port of the terminal network control device provided on each user side. The data sent from the sensor was decoded with a bit length according to this management information.

[0005]

Since the conventional telemetering system is constructed as described above, the meter or sensor connected to a certain port of the terminal network control device has a character of a bit length different from that of the previous one. When the meter or sensor which transmits data is replaced, the center side cannot decode the data sent from the replaced meter or sensor. That is, in this case, the computer on the center side NAK which indicates that the received data cannot be decrypted.
(Negative acknowledge) signal,
Alternatively, a reorder for requesting retransmission of data is sent to the terminal network controller, and then awaiting a return from the terminal network controller. If the data sent from the terminal network controller is undecipherable again, the center retransmits the NAK signal or reorder to the terminal network controller. Even if the above operation is repeated a predetermined number of times, if the decipherable data is not transmitted from the terminal network control device side, the center side executes a predetermined error process.

As described above, in the conventional telemetering system, when the meter or sensor connected to the terminal network control device is replaced with one having a different bit length, the center side collects the information of the meter or sensor. There was a problem that I could not. In order to solve this problem, a method has been proposed in which the terminal network controller automatically determines the bit length of received data. Specifically, of the plurality of character data included in the data packet received from the terminal device using the telephone line, the logical inversion interval in the first character data is measured using a timer function or the like, and The bit length of the received character data is discriminated based on the measurement result, and the character data of the data packet received as the discriminated bit length data is decoded. However, if this bit length automatic discrimination method is adopted, it is necessary to measure the logical inversion interval of the received character data, so the input port for connecting the telephone line and the terminal network control device has a general-purpose function. It was not possible to be a fundamental solution to the above mentioned problem, with the limitation that it was limited to those with.

Although not applied to a telemetering system, generally, Haye is generally used as a data format automatic discrimination method used for general-purpose modem control commands.
There is an AT command provided by s company (USA). This automatic data format discrimination method has the same data bit length excluding stat bits and stop bits, for example, 8 bits without parity bits (8 + 0 = 8), 7 bits with even parity bits (7 + 1 = 8) and 7 There is a limitation that it is applied only to the same data bit length such as odd parity bits (7 + 1 = 8). Therefore, this data format automatic discrimination method has a problem that it is not possible to discriminate data bit lengths that are completely different.

Therefore, an object of the present invention is to automatically discriminate an arbitrary bit length of received data without any special restriction on the function of an input port for inputting data sent from a terminal device. An object of the present invention is to provide an automatic data length discriminating apparatus which can eliminate the indecipherability of data on the center side.

[0009]

An automatic data length discriminating apparatus according to the present invention receives data from a terminal device in a data collecting system for collecting packets of a plurality of character data from a terminal device using a telephone line. It is an automatic data length determination device that automatically determines the bit length of data. Specifically, a mode setting means for setting a mode for normally receiving character data of a predetermined bit length transmitted from the terminal device, and a plurality of the character data included in a data packet transmitted from the terminal device. Of the receiving means for receiving the first character data in accordance with the mode set by the mode setting means, and whether or not the bit length of the first character data and the predetermined bit length match when received by the receiving means. And a determination means for determining the bit length of the character data based on the detection result of the detection means.

Further, in the above-mentioned configuration, the control means controls the mode setting means to change the setting mode to a mode for recovering the inconsistency in response to the inconsistency detection by the detecting means. It may be configured.

[0011]

In the automatic data length discriminating apparatus according to the present invention, it is noted that the plurality of character data included in the data packet sent from the terminal device has a peculiar bit length, and the receiving means sets the mode. Regarding the data received according to the mode set by the setting means, the detecting means
It is detected whether or not the bit length matches a predetermined bit length according to the setting mode. Then, the discrimination means discriminates the bit length of the received data based on the detection result of the detection means. As a result, the bit length of the data sent from the terminal device is automatically determined. Also, at the center,
By decoding the data sent from the terminal device according to the mode set by the mode setting means, even if the terminal device such as the meter or the sensor is replaced with a device having a different bit length, the data transmitted from the terminal device Impossible to decipher is prevented.

[0012]

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of a center side network control device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a schematic configuration of a telemetering system to which the present invention can be applied.

In FIG. 2, the host computer 1 on the center side is a network control unit on the center side (hereinafter, C-NCU).
Called) 2 and is connected to the exchange 3. A plurality of telephone lines L1 to Ln are connected to the exchange 3.
Each telephone line L1 to Ln is led to each user.
In each user, a terminal network control device (hereinafter, T-NC
4). T-NC in each user
U4 is connected to telephone lines L1 to Ln, respectively. Further, each T-NCU 4 has a plurality of ports, and meters or sensors that are the targets of information collection are connected to the ports. In the telemetering system shown in FIG. 2, as an example, a water meter 5 and a gas meter 6 are connected to each T-NCU 4.

In the telemetering system shown in FIG. 2, when the host computer 1 issues an order requesting the transmission of data from a certain meter or sensor in a user, this order is given to the exchange 3 via the C-NCU 2. Be done. The exchange 3 which has received the order transmits the order to the T-NCU 4 of the designated user via the telephone line corresponding to the telephone number included in the order. T-NCU4 that received the order
Collects information from a meter or sensor connected to the port specified in the order, edits it in the form of a data packet, and sends it to the telephone line. The data from the T-NCU 4 is sent to the center side via the exchange 3.
At the center, the data sent from the exchange 3 is C-
The NCU 2 decodes and outputs to the host computer 1.
The host computer 1 calculates the usage charge or performs other processing on the data received from the C-NCU 2 and stores it in a data memory (not shown). In addition, the host computer 1 displays the processing result on a display or prints it out as necessary.

A more detailed structure of the C-NCU 2 shown in FIG. 2 is shown in FIG. In FIG. 1, a CPU 201 includes a ROM 202 that stores program data and a RAM that stores data necessary for performing various processes.
And 203 are connected. CPU201 is ROM2
The operation is performed according to the program data stored in 02. Further, a serial I / O 205 is connected to the CPU 201. The serial I / O 205 serially inputs and outputs data, and has an output interface 208.
It is connected to the host computer 1 via. Therefore, the CPU 201 can transmit serial data with the host computer 1 via the serial I / O 205 and the serial interface 208.

Further, the CPU 201 has a serial I /
O206 is connected. The serial I / O 206 is an IC (integrated circuit) having a simple memory function, has a configuration not including a general-purpose input port, and is connected to the modem 209. The modem 209 has a line interface 2
It is connected to the exchange 3 via 10. Modem 209
When a carrier signal is input from the exchange 3 via the line interface 210, the CD (carrier)
r detect) signal is activated. Also, the modem 2
09 is RS (r input from the serial I / O 206
When the request to send signal is activated,
In response, the carrier signal is sent to the exchange 3 via the line interface 210. When transmitting data from the serial I / O 206, the RS signal is activated and serial data is output from the output terminal TXD to the modem 209. As a result, the modem 209 outputs serial data to the exchange 3 via the line interface 210. On the other hand, when receiving data, the modem 209 first detects the input of the carrier signal from the exchange 3 and activates the CD signal. Therefore, the serial I / O 206 monitors the CD signal and fetches the data given from the modem 209 to the input terminal RXD when the CD signal is activated.

The CPU 201 is a serial I / O 206.
To the character mode setting signal MD. On the contrary, the serial I / O 206 gives the CPU 201 an interrupt signal (polling) IT. Serial I / O 206 is a CPU
When the character mode setting signal MD is given from 201, the data relating to the bit length of the receivable data is set in the internal memory based on the signal MD. this,
Hereinafter referred to as the character mode setting function. When the serial I / O 206 receives the data provided from the exchange 3 based on the bit length data set by the character mode setting function, the bit length of the character of the received data matches the set bit length. However, if a framing error (an error that occurs when the stop bit is not detected in the asynchronous method) occurs, the framing error is detected, and the interrupt signal IT is given to the CPU 201 accordingly. This interrupt signal IT may be polling.
In this way, the serial I / O 206 variably sets the start-stop synchronization type signal processing method with the exchange 3 in accordance with the character mode setting signal MD given from the CPU 201.

Further, the CPU 201 is connected with a parallel I / O 207 which inputs and outputs data in parallel.
An input / output device interface 211 is connected to the parallel I / O 207. I / O device interface 2
11, LED 212, buzzer 213, operation button 2
Various input / output devices such as 14 are connected.

FIG. 3 is a diagram showing a format of a data packet sent from the T-NCU 4 shown in FIG. 2 to the C-NCU 2.

In FIG. 3, the data packet is divided into a header part, a data part and an end part. In the header portion, a code STX (start) indicating the start of the data packet is
of text) is included. 02 _{H for} this STX
It is predetermined to use a numerical code (hexadecimal display). The data section includes the original information to be transmitted to the center (for example, meter number, detected value, etc.). The end part has a code E indicating the end of the data packet.
TX (end of text) is included. This ET
It is predetermined that X is a numerical code of 03 _H (hexadecimal notation). The header part and the end part each include one character data (STX, ETX), and the data part includes a plurality of character data.

FIGS. 4A and 4B are waveform charts showing the case where a framing error is detected in the STX shown in FIG.

FIG. 4A shows an STX bit pattern of 5-bit character data. Figure 4
(B) shows an STX bit pattern of 7-bit character data. For example, assuming that the 5-bit length character mode is set, if 7-bit length character data is transmitted, the serial I / O 206 generates a framing error at time T1 shown in FIG. To detect.

FIG. 5 is a flow chart for explaining the overall operation of CPU 201 shown in FIG.

FIG. 6 is a flow chart showing in more detail the operation of the characteristic portion which is of interest to the present embodiment among the operations executed by the CPU 201 shown in FIG.

The operation of the embodiment shown in FIGS. 1 and 2 will be described below with reference to FIGS. 4 (a) and 4 (b) to 6.

In the present embodiment, it is assumed that there are two types of data to be transmitted to the center side, that is, including 5-bit character data or 7-bit character data.

First, the overall operation of the CPU 201 will be described with reference to FIG. First, in step S1 (abbreviated as S1 in the figure), the CPU 201 performs various initial settings necessary for starting the operation. Subsequently, the CPU 201 performs monitoring control of the telephone line in step S2. In this telephone line monitoring control, which telephone line is currently being used or from which telephone line the data has been sent is monitored. Next, in step S3, the CPU 201 controls data transmission / reception with the T-NCU 4. That is, the CPU 201 executes the T-NC performed by the modem 209 in step S3.
It controls the data transmission process to U4 and the data reception process from T-NCU4. Next, the CPU 201
Performs a communication process with the host computer 1 on the center side in step S4. After that, the CPU 201
In step S5, the LED 212 and the buzzer 21
3. Input / output control of data with respect to input / output of the operation button 214 and the like is performed. Then, the process returns to step S2, and the process is repeated in the same manner.

The processing flow shown in FIG. 6 shows in more detail a part of the transmission / reception control with the terminal executed in step S3 in FIG. 5, and shows the operation of the characteristic part of this embodiment. Next, with reference to FIG. 6 together with FIG. 3 and FIG. 4, the operation of the CPU 201, which is a feature of this embodiment, will be described below.

In the processing shown in FIG. 6, a call arrives at the C-NCU 2 via the exchange 3 in FIG. 2, and the C-NCU 2 and the data terminal (water meter 5 or gas meter 6) of the other party respond to the call. This is a process started when a telephone line is established between the two and data communication becomes possible.

First, in step S201, the CPU
201 sets beforehand the character mode of the C-NCU 2 to a 5-bit length. That is, the character mode setting signal MD is given to the serial I / O 206, and the serial I / O 206
The character mode data having a length of 5 bits is set in the internal memory of 206. In response to this, the serial I / O 206
STX of the character data that can be received in the internal memory of
As the bit pattern of, the STX pattern of 5 bits length is set by the combination of the mark and space of (001001) as shown in FIG. Next CP
The U201 monitors the time-out when the signal to be received next is not received in response to the establishment of the telephone line in step S202, and when the time-out occurs, the process proceeds to the next step S209 to perform the error process. Run. In the time-out monitoring in step S202, a period until the carrier signal corresponding to the signal to be received after the line is established is measured, and the time period exceeds the predetermined time (for example, 6 seconds). If not received, the error process of step S208 is executed.

If a predetermined carrier signal is detected within a predetermined time after the line is established in the processing of step S202, that is, the carrier detection signal C is received via the modem 209.
D is given to the serial I / O 206, and accordingly the CPU2
When 01 is notified, the process of step S203 is executed.

In step S203, the CPU 201
Determines whether the aforementioned Fleming error is detected. The serial I / O 206 inputs the signal given via the modem 209 via the input terminal RXD, and in response, compares the STX of the header portion with the STX pattern of 5-bit length stored in advance in the internal memory. At this time, while the STX 7-bit mark stored in the memory in advance matches the STX 7-bit pattern of the received character data, no Fleming error is detected by the serial I / O 206.
1 shifts to the processing of step S204 and determines whether or not STX is received. At this time, 5-bit length STX
While is not received, the process returns to step S202 again, and the above-described process is repeated.

In the processing of step S203, when the serial I / O 206 detects a framing error and gives an interrupt signal IT to the CPU 201 in response, the CPU 20
1 shifts to the processing of step S205 accordingly. That is, the CPU 201 responds to the fact that the interrupt signal IT is given in the process of step S203 described above.
In response to the data that cannot be received in the current character mode, that is, the character data of 7-bit length is transmitted, the character mode setting signal MD is again given to the serial I / O 206 to change the setting to the character mode of 7-bit length. To do. For details, see Serial I / O 206.
In its internal memory as shown in FIG.
A 7-bit pattern with a combination of space and mark of (0000) is stored.

If STX reception is confirmed in the discrimination processing of step S204 as described above, thereafter, ETX reception processing of the data portion and the end portion shown in FIG. 3 based on the character mode being 5 bits long. Is step S2
06 and the processing of step S207,
Then, the process proceeds to the next process of step S208.

When the setting is changed to the character mode of 7-bit length through the processing of step S205, the subsequent reception of the data portion is performed in accordance with the fact that the character mode is 7-bit length and the reception processing of the data portion and the ETX reception. The process is performed in the process of S206 and step S207. After that, the processing shifts to the next processing.

Although the above-mentioned embodiment is applied to a so-called telemetering system, the present invention is similarly applied to other data collecting systems as long as the data collecting system collects data from terminals. It is possible to apply.

[0039]

As described above, according to the present invention, the bit length of the data sent from the terminal device can be automatically determined. With this, when the center side decodes the data from the terminal device, even if the terminal device side changes the bit length of the data for data communication independently, the received data can always be accurately decoded and the center side data There is an effect that it is possible to prevent a situation in which it becomes impossible to collect.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a center side network control device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a schematic configuration of a telemetering system to which the present invention can be applied.

FIG. 3 is a diagram showing a data packet format adopted in a telemetering system.

4 (a) and (b) are STX shown in FIG.
6 is a waveform diagram showing a case where a Fleming error is detected in FIG.

5 is a flowchart for explaining the overall operation of the CPU shown in FIG.

FIG. 6 is a flowchart showing an operation performed by a CPU shown in FIG.
It is a flowchart which shows operation | movement of the characteristic part which is interesting for a present Example in detail.

[Explanation of symbols]

 1 host computer 2 center side network control device 3 exchanges L1-Ln telephone line 4 terminal network control device 5 water meter 6 gas meter 201 CPU 202 ROM 203 ROM IT interrupt signal MD character mode setting signal Or shows a considerable part.

Claims (2)

[Claims] 1. A data collection system for collecting a packet of a plurality of character data from a terminal device using a telephone line, and a data length automatic discrimination device for automatically discriminating a bit length of data received from the terminal device. A mode setting means for presetting a mode for normally receiving character data of a predetermined bit length transmitted from the terminal device, and a plurality of the data packets included in a data packet transmitted from the terminal device. Among the character data, receiving means for receiving the first character data in accordance with the mode set by the mode setting means, and the bit length of the first character data and the predetermined bit length match when received by the receiving means. Based on the detection result of the detection means, which detects whether or not to do, And a discrimination means for discriminating the bit length of the serial character data, data length automatic determination device. 2. The control means for controlling the mode setting means to change the setting mode to a mode for recovering the inconsistency according to the inconsistency detection by the detecting means. Data length automatic discriminating device.