JPH01300731A - Modem device - Google Patents

Abstract

PURPOSE:To reduce the occurrence of faults by giving a function which automatically recognizes the data format before getting into a communication state to the title device and ignoring flow control codes which do not match the data format, but treating codes matching the format only as the flow controlling codes while the communication state continues. CONSTITUTION:This MODEM device automatically recognizes the data format upon receiving command data from information processing terminal equipment 1 before getting into a communication state with a communication partner and stores flow control codes corresponding (according) to the format in a RAM 8. Upon receiving transmitting data from the equipment to its communication partner or from the partner to its own equipment 1 after stating the communication state, the MODEM device monitors the flow control codes corresponding to the data format and treats those matching the data format only as the flow controlling codes by ignoring those which do not match the format. On the other hand, the flow control codes stored in the RAM 8 are sent to the information processor 1 or communication partner while the communication state continues.

Description

Detailed Description of the Invention (a) Industrial Application Field This invention is provided between an information processing device such as a personal computer and a public line, has a built-in microprocessor, and has a built-in microprocessor. The present invention relates to a modem device that performs modulation/demodulation control of communication information.

(b) Prior Art Generally, when a digital processing device such as a personal computer communicates with a destination via a telephone line, a modem device is used. Conventionally, this modem device does not have a built-in buffer, and simply converts digital data from a computer into an analog signal and sends it to the telephone line, or conversely, converts analog signals from the telephone line into digital signals and inputs them to the computer. Some modems have only a digital-to-analog conversion function, while others have a built-in buffer in addition to a digital-to-analog conversion function and can determine what kind of data is being transmitted, and the modem can recognize flow control codes.

(C) Problems to be Solved by the Invention Among the conventional modem devices described above, those that do not have a built-in buffer cannot monitor transmitted data at all.

On the other hand, a modem device with a built-in buffer has several types of fixed codes to be treated as flow control codes, monitors each byte of data being transmitted, and selects data that exactly matches the code as a control flow code. I'm handling it. The modem knows in advance that the data sent from the personal computer is a command, and can recognize what data format the command is in.

However, when in a data communication state, the modem cannot recognize what data is being transmitted, and therefore it has been impossible to accurately determine the data format. Therefore, there are cases where codes other than flow control codes are treated as flow control codes, resulting in problems such as buffer overflow, communication failure, and destruction of transmitted data.

This invention was made by focusing on the above problem, and includes a function to automatically recognize the data format before entering the communication state, and during the communication state, flow control codes that do not match the data format are ignored. The object of the present invention is to provide a modem device that can reduce the occurrence of communication failures by handling only matching codes as flow control codes.

(d) Means and operation for solving the problems The modem device of the present invention has a built-in microcomputer, and uses data received from an information processing terminal device such as a personal computer before entering a communication state. , a data format recognition means for recognizing a data format, a storage means for storing the recognized data format, and a flow control code for monitoring a flow control code corresponding to the data format stored in the storage means during a communication state. It is characterized by comprising a monitoring means, and a flow control code sending means for sending a flow control code corresponding to the data format stored in the storage means to the information processing terminal device or the communication partner during a communication state. There is.

This modem device receives command data from an information processing terminal device, automatically recognizes the data format before entering communication status with the other party, and flows according to (according to) the recognized data format. The control code is stored in the storage means. When the communication state is entered, when data is received from the information processing terminal to the other party, or from the other party to the information processing terminal in question, the flow control code corresponding to the data format is monitored. If the flow control code does not match, it is ignored, and only if the flow control code fails, it is treated as the flow control code. On the other hand, the flow control code stored in the storage means is sent to the information processing device or the communication partner during the communication state.

(E) Examples The present invention will be explained in more detail with reference to Examples below.

FIG. 1 is a block diagram showing the hardware configuration of a modem device in which the present invention is implemented. This modem device is
It is connected to a telephone line 13 via a communication transformer 12. It is also connected to a data processing terminal device 1 such as a personal computer via an R3-2320 interface 2. Between the communication transformer 12 and the data processing terminal device 1 are a hybrid circuit 11, a modem LSr9, a full-duplex type serial 0 port 10, a CPU 5, and a serial IO port 3.
are provided in order. CPU5 is 80M7, RAM
8 constitutes a microcomputer, which performs overall control of the modem.

The hybrid circuit 11 functions as a driver/receiver, and as is generally well known, the modem LSI 9 can be configured with various functions under external control, such as switching the transmission speed, It is possible to turn on/off echo for transmitted data, set the carrier interruption time that leads to line disconnection, and set other functions.

In this modem device, the CPU 5 allows two types of transmission modes to be used. The first mode is from the data processing terminal device 1 to the R3-232C interface 2,
0 port 3, connected to the CPU 5 via the bus 4a,
According to the instructions from the data processing terminal device "1", the CPU 5
uses the bus 6 that is directly connected to the modem LSI 9 to perform settings etc. directly on the modem LSI 9 (command mode)
It is. In the second mode, from the data terminal processing device 1,
R3-232C interface 2, IO port 3, data bus 4a, CPU 5, data bus 4b, IO port)
10. Modem LS I 9, hybrid circuit 10
, which uses a system connected to the telephone line 13 via the communication transformer 11 (communication state mode).

In the second mode, the CPU 5 has the function of transferring data from the data processing terminal device 1 side to the modem LSI 9 side and data from the modem LSI 9 side to the data processing terminal device 1 side. If data cannot be transferred due to a difference in transmission speed between the device 1 and the modem LSI, etc., it has a function (buffer function) to temporarily store data using a part of the RAM 8 (RAM buffer area). Note that the RAM 8 is backed up by a battery 8a.

2 to 4 are flowcharts showing the configuration of a control program executed by the CPU 5 of the modem device of the embodiment.

The operation of the apparatus of the above embodiment will be explained below with reference to these flowcharts.

First, when the program is started by turning on the power, etc., various flags, registers, and memories are initialized [step ST (hereinafter abbreviated as ST) (2)], and then a command input state is entered (Sr2). From the data terminal processing device 1, R
When a command is input via the 3-232C interface 2, rO boat 3, and bus 4a, an automatic data format recognition processing subroutine (see FIG. 3) is executed at any time (Sr1). In addition to the function of automatically recognizing the data format based on the input command, this automatic recognition processing subroutine also has the function of automatically recognizing the data format based on the input command.
It also has the function of storing each in the N/X0FF code reference data storage area. Here, the XON code is 1-byte data that indicates that reception is possible, and the X0FF code is 1-byte data that indicates that reception is not possible.

The bit length of the input data is usually 8 bits or 7 bits and 1 parity bit, so in the data format inspection process, it is possible to choose between 8 bits with no parity, 7 bits with even parity, 7 bits with odd parity, and 7 bits with fixed parity. A process is executed to detect that. That is, when entering this subroutine, as shown in FIG. 3, data format checking processing is first executed (Sr31), and it is determined whether the input data has 8-bit parity (Sr32) or 7-bit even parity (Sr32).
34) and 7-bit odd parity (Sr36). If there is no 8-bit parity, 5T
32 becomes YES, code 11H is stored in the XON code reference data storage memory N, and X0
Code 13H is stored in the FF code reference data storage memory F (Sr33), and the process returns. In addition, in the case of 7-bit even parity, the determination of Sr14 becomes YES, ILH is stored in memory N, and memory F
93H is stored in (Sr35) and returns. Furthermore, in the case of 7-bit odd parity, the determination of Sr16 becomes YES, and code 91H is stored in memory N.
13H is stored in memory F (Sr37), and the process returns.

If the data has fixed 7-bit parity, memory N
Store code 91H in memory F, store code 93H in memory F (5T3B), and return.

Here, the stored data IIH, 13H19111,
The data 93H is data expressed in hexadecimal, and these four types of data are control data normally employed in the X ON/XOF I control system. III(,
91H is XON:I-)", 131(, 93H is X0F
It is an F code.

Next, in the main routine, if the input command is a dial command (Sr4), the determination is YES and data communication is started (Sr1).

In the data communication state, next, it is determined whether there is data received from the other party (5T7), and if it is not received data, it is determined whether or not the communication state is in progress (5T8). If the communication state is, the RAM buffer is The process moves to the inspection processing subroutine (Sr1).

In the RAM buffer inspection processing subroutine, the free area of the RAM buffer is inspected. In other words, as shown in FIG. 4, it is determined whether the RAM buffer is free for a specified number or more (5T91), and if the RAM buffer is free for a specified number or more, then it is determined whether or not flag b is O. Shiku5T92),
If flag b is O, the contents of memory N, that is, XO
Transfers the N code to memory X, transmits the contents of memory X (ST93), sets flag b to 1, and returns. If b is not O in 5T92, it is already XON
The code is assumed to have been sent and is returned as is. By transmitting the contents of this memory X, the communication partner is informed that there is an empty area in the RAM buffer.

In addition, in Sr11, if the RAM buffer is not more than the specified number of free spaces, it is determined whether the buffer flag b is 1 or not (5T95), and if b = 1, the contents of the memory F, that is, the X0FF code are transferred to the memory At the same time, the contents of the memory X are transmitted (ST96). This transmission is a process for notifying the other party that the free area of the RAM buffer is less than a specified number. In Sr15, if b is not 1, the X0FF code is
This means that the contents are stored in the memory and sent, and the contents are returned as is.

Next, in the communication state, if there is received data in Sr1, 1 byte of received data is stored in memory Y (STIO). Then, the contents of memory Y, that is, the received data, and the XON code, which is the contents of memory N, are compared (STII). If the two match, data transmission is started to the other party (5T12) and the process returns to Sr1. On the other hand, if the received data and XON code do not match,
Next, compare the received data Y and the contents of memory F, that is, the X0FF code (5T13), where:
If the codes match, data transmission will be stopped.5T
14), the process returns to Sr1, but if the contents of memory F and the contents of memory Y still do not match, the contents of memory Y are transferred to RAM buffer 8 and stored (ST15).
).

The RAM buffer 8 includes a RAM buffer for transferring data received from the data processing terminal device 1 side to the modem LSIQ side, and a RAM buffer for transferring data received from the modem LSI 9 side to the data terminal processing device 1 side. R for transfer
There are two types of AM buffers. The contents of the reception buffer Y are transferred to the RAM buffer so that they are applied to the receiving side.

In Sr4, if it is not a dial command, C
PU5 performs processing according to the command (Sr5)
, returns to Sr1.

(f) Effects of the Invention According to this invention, before entering a communication state, a command is received from an information processing terminal device, the format of the command data is automatically recognized, and a flow control code corresponding to the data format is stored. In the reception state, the flow control code corresponding to the data format is monitored, and for example, the data format input from the other party matches the flow control code stored in the storage means. We will monitor whether or not.

If there is a match, use the flow control code as is,
If they do not match, they are ignored, so even non-flow control codes are rarely treated as flow control codes, which can lead to problems such as buffer overflows, communication failure, and corrupted transmitted data. This enables highly accurate transmission.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the hardware configuration of a modem device showing an embodiment of the present invention, FIG. 2 is a flow diagram of the main routine of the control flow showing the program structure of the CPU of the device of the embodiment, and FIG. 4 is a flowchart showing a data format automatic recognition processing subroutine of the same main routine, and FIG. 4 is a flowchart showing a RAM buffer inspection processing subroutine of the same main routine. l: Data processing terminal device, 3/10: I○ boat, 5: CPU
. 8: RAM, 9: Modem LSI, 13:
telephone line. Patent Applicant Tateishi Electric Co., Ltd. Agent Patent Attorney Shigeru Nakamura Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] (1) Provided between the information processing terminal device and the public line,
A modem device that performs modulation and demodulation control of communication information, comprising: a data format recognition unit that recognizes a data format based on data received from the information processing terminal device before entering a communication state; and a storage unit that stores the recognized data format. , flow control code monitoring means for monitoring a flow control code corresponding to a data format stored in the storage means during a communication state; and flow control code monitoring means for monitoring a flow control code corresponding to a data format stored in the storage means during a communication state; A modem device comprising: flow control code sending means for sending a flow control code corresponding to a data format stored in the means.