Short-wave radio facsimile communication module and method for realizing short-wave radio facsimile communication

Abstract

The invention provides a short-wave radio facsimile communication module and a method for realizing short-wave radio facsimile communication, and belongs to the technical field of short-wave communication. The short-wave radio facsimile communication module comprises a central control unit, a storage unit, a subscriber line interface circuit, an initialization module, a configuration module, a log module, a facsimile communication state machine module, a G3 facsimile machine facsimile communication module, a facsimile data encryption and decryption module and a waveform protocol processing module. According to the short-wave radio facsimile communication module, through cooperative work of all the modules, connection with a special line or an external line of a G3 facsimile machine is achieved, multiple facsimile coding modes are supported, facsimile data are encrypted and decrypted, and the communication safety is improved; and real-time service scheduling is realized through the state machine, so that efficient and reliable operation of the system is ensured. According to the method for realizing the fax communication of the short-wave radio station, the flow of sending and receiving the fax is specified in detail, different configuration modes are compatible, and the problems in the prior art are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of short-wave communication, and particularly to a short-wave radio fax communication module and a method for realizing short-wave radio fax communication. Background Art

[0002] Short-wave communication radios are crucial in scenarios such as emergency communication, maritime communication, and military communication due to advantages such as long communication distance, small size, and strong anti-interference ability. Fax communication, as a recording communication for transmitting static images, has real-time recording and facsimile transmission properties and is widely used in multiple fields, especially in military communication. However, existing short-wave radio fax communication has problems such as low transmission rate, insufficient security, and difficulty in being compatible with various types of G3 fax machines. There is an urgent need for a short-wave radio fax communication module and method that can solve the above problems. Summary of the Invention

[0003] The present invention aims to solve the problems of low transmission rate, insufficient security, and compatibility difficulties existing in existing short-wave radio fax communication, and provides a short-wave radio fax communication module and a method for realizing short-wave radio fax communication.

[0004] The specific technical solutions are as follows: A short-wave radio fax communication module includes: a central control unit, a storage unit, a user line interface circuit, an initialization module, a configuration module, a log module, a fax communication state machine module, a G3 fax machine fax communication module, a fax data encryption and decryption module, and a waveform protocol processing module; the central control unit is electrically connected to the storage unit, the user line interface circuit, and an embedded Modem respectively; the initialization module, the configuration module, the log module, the fax communication state machine module, the G3 fax machine fax communication module, the fax data encryption and decryption module, and the waveform protocol processing module are stored in the Flash memory inside the central control unit in the form of software binary codes; the module is connected to a G3 fax machine through a two-wire telephone line in a dedicated line or outside line manner to realize fax communication between the G3 fax machine and the short-wave radio, the fax data communicates with the waveform module according to the protocol, the module implements the LwIP protocol and the waveform module protocol, and the waveform module and the fax communication module use UDP transmission.

[0005] In the above short-wave radio fax communication module, the storage unit includes a 1MB-capacity SRAM memory CY62157 and a 1MB Flash memory W25X80, which are used to store fax data, fax capability parsing information, and buffer data after encryption and decryption processing, and support on-demand dynamic allocation of up to 10 pages of fax data.

[0006] The above-mentioned shortwave radio fax communication module, wherein the user line interface circuit is the SLIC circuit Ag1170, which is used for off-hook and on-hook signal detection, line feeding, and ring signal generation, supports dedicated line or outside line connection modes of two-wire telephone lines, and is compatible with information security laser dedicated fax machines and shipboard secure fax machines of type G3 fax machines.

[0007] The above-mentioned shortwave radio fax communication module, wherein the fax communication state machine module realizes real-time scheduling of services such as PSTN fax communication, waveform protocol processing, off-hook and on-hook detection, dual-tone multi-frequency DTMF signal recognition, and ring signal generation through a state machine. After the system is powered on, it successively goes through the Initial state and the Idle monitoring state. The state transition complies with specific conditions and routes, and network reception is realized through interrupt callbacks.

[0008] The above-mentioned shortwave radio fax communication module, wherein the G3 fax machine fax communication module includes an embedded Modem MT9234, which communicates with the Modem through the internal UART of the central control unit, and realizes fax sending and fax receiving in accordance with the T.30 fax communication protocol. In the C stage of the T.30 fax protocol, a stop-and-wait flow control mechanism is adopted to solve the complete and reliable transmission of the entire fax data frame. The stop-and-wait flow control is realized by monitoring the (XON / XOFF) characters on the Modem line through software. The UART baud rate is set to 19200bps, and the line rate supports 9600bps or 11400bps. When receiving a fax, the UART is set to a baud rate of 57600bps for reception, and a large buffer is set to avoid the need for flow control. It realizes multiple limited-time response processes in the call establishment, pre-message preparation process, and post-message release process of the G3 fax machine, and the reliable and complete reception and transmission of the fax encoded data frame in the message. The fax encoded data supports MH\MHR\MMR encoding methods.

[0009] The above-mentioned shortwave radio fax communication module, wherein the fax data encryption and decryption module encrypts and decrypts the fax image data, and uses the Blowfish symmetric block cipher algorithm with variable key length to encrypt and decrypt the fax page encoded data to ensure that the fax data transmitted by the radio cannot be deciphered and improve communication security.

[0010] The above-mentioned shortwave radio fax communication module, wherein the waveform protocol processing module realizes protocol communication with the shortwave radio waveform module. The data packet format definition includes version, length, source module encoding, target module encoding, type, checksum, and message payload. It is transmitted using the UDP protocol and has a data confirmation mechanism and a communication mechanism, which stipulate the waiting time and retransmission of data packets.

[0011] The above-mentioned shortwave radio fax communication module, wherein the hardware part further includes LM3S9B96 with an ARM Cortex-M3 main controller core, an embedded Modem MT9234, a latch 7416373, a DTMF signal recognition circuit HT9172, and a power supply circuit. Each hardware component works together to support the hardware functions of the fax communication module.

[0012] The above-mentioned shortwave radio fax communication module, wherein the software system includes a HAL (Hardware Abstraction Layer) based on the circuit layer, an OS (Operating System) layer, and a logical function application layer; the HAL hardware abstraction layer includes UART, Timer, GPIO, SRAM, FLASH, SLIC, and Modem driver programs; the logical function application layer includes an initialization module, a state machine, a fax data encryption and decryption module, a configuration module, a log module, a PSTN calling sending module, a PSTN called receiving module, and a waveform protocol transceiver processing module.

[0013] The above-mentioned shortwave radio fax communication module, wherein the analog debugging software supports waveform protocol transceiver communication, can conveniently receive fax data, send fax data through the network, and can view fax image data in the form of Tiff files. The data display window displays communication data in real time.

[0014] The above-mentioned shortwave radio fax communication module, wherein the initialization module performs power-on detection and initialization of system resources; the configuration module configures network parameters and line connection methods; the log module records the system activity status in real time and generates a communication report.

[0015] The above-mentioned shortwave radio fax communication module, wherein the PSTN calling sending module uses a stop-and-wait flow control method in stage C of the T.30 fax communication protocol, and the waveform protocol processing module uses a request-confirmation protocol-based flow control and retransmission error control method.

[0016] The above-mentioned shortwave radio fax communication module, wherein the waveform protocol processing module implements the LwIP protocol, and the waveform protocol is programmed and implemented in the way of Raw / Callback API callback.

[0017] The present invention also provides a method for realizing shortwave radio fax communication, which applies the above-mentioned shortwave radio fax communication module, and includes sending a fax and receiving a fax; when sending a fax, the fax communication module receives the fax sent by a G3 fax machine, communicates and stores data through the T.30 fax communication protocol, encrypts it and then transmits it to the service unit through the network, and is transmitted by the shortwave radio; when receiving a fax, the shortwave radio sends the encrypted fax data to the fax communication module, decrypts it and then starts the fax sending process, and communicates with the G3 receiving-end fax machine according to the T.30 fax communication protocol.

[0018] The above method for realizing shortwave radio fax communication, wherein, when sending a fax, when configured in the external line mode, the calling G3 fax machine picks up the handset and dials *# to start the receiving process, and sends according to the start button in accordance with the call establishment phase A of the T.30 fax communication protocol; when configured in the dedicated line mode, the G3 fax machine directly connects and receives the fax message after pressing the start button; when receiving a fax, in the external line mode, the on-hook and off-hook status of the line is detected, and a ringing signal is sent to notify the receiving party to pick up the handset. In the dedicated line mode, the line is always off-hooked, and an attempt is directly made to connect in phase A. After successful connection, communication is carried out according to the T.30 fax communication protocol.

[0019] The present invention has the following beneficial effects: The shortwave radio fax communication module of the present invention realizes dedicated line or external line connection with the G3 fax machine through the collaborative work of each module, supports multiple fax coding methods, encrypts and decrypts fax data, and improves communication security; the service is scheduled in real time through the state machine, ensuring the efficient and reliable operation of the system. The method for realizing shortwave radio fax communication details the processes of sending and receiving faxes, is compatible with different configuration methods, solves the problems in the prior art, and is applicable to fields such as emergency communication, maritime communication, and military communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is the schematic diagram of shortwave radio fax communication provided by the embodiment of the present invention; Figure 2 It is the schematic diagram of the system hardware of the shortwave radio fax communication module provided by the embodiment of the present invention; Figure 3 It is the system architecture diagram of the shortwave radio fax communication module provided by the embodiment of the present invention; Figure 4 It is the schematic diagram of the fax communication module as a called receiver provided by the embodiment of the present invention; Figure 5 It is the schematic diagram of external line connection and external line setting operation provided by the embodiment of the present invention; Figure 6 It is the schematic diagram of dedicated line connection and dedicated line setting operation provided by the embodiment of the present invention; Figure 7 It is the flowchart of the fax communication module receiving fax communication from the G3 fax machine provided by the embodiment of the present invention; Figure 8 It is the flowchart of the fax data encryption process provided by the embodiment of the present invention; Figure 9 It is the flowchart of the fax data network transmission provided by the embodiment of the present invention; Figure 10 It is the schematic diagram of the fax communication module as a calling transmitter provided by the embodiment of the present invention; Figure 11 Flow chart of fax data network reception provided by an embodiment of the present invention; Figure 12 Flow chart of decryption processing and sending G3 fax machine for fax data network reception provided by an embodiment of the present invention; Figure 13 Flow chart of fax communication module sending G3 fax machine fax communication provided by an embodiment of the present invention; Figure 14 Schematic diagram of protocol data packet format of fax communication module and short - wave waveform module provided by an embodiment of the present invention; Figure 15 Modem rate diagram of T.30 fax communication process provided by an embodiment of the present invention; Figure 16 Schematic diagram of fax data format definition provided by an embodiment of the present invention; Figure 17 System software state transition diagram of fax communication module provided by an embodiment of the present invention; Figure 18 Flow chart of Blowfish encryption of fax data provided by an embodiment of the present invention; Figure 19 Flow chart of Blowfish decryption of fax data provided by an embodiment of the present invention; Figure 20 Schematic diagram of internal implementation process of network Socket initialization function of waveform protocol processing module provided by an embodiment of the present invention; Figure 21 Schematic diagram of stop - and - wait flow control of fax data provided by an embodiment of the present invention; Figure 22 Flow chart of sending fax data with stop - and - wait flow control provided by an embodiment of the present invention; Figure 23 Schematic diagram of protocol - based flow control of waveform protocol processing module provided by an embodiment of the present invention; Figure 24 Network simulation test diagram of fax communication module provided by an embodiment of the present invention; Figure 25 Software interface diagram of waveform protocol simulation test of fax communication module provided by an embodiment of the present invention. Detailed implementation manners

[0021] The technical solution of the present invention will be further described below in conjunction with the accompanying drawings and through specific implementation manners.

[0022] Among them, the attached drawings are only for illustrative purposes, showing only schematic diagrams rather than actual diagrams, and should not be construed as a limitation to this application; in order to better illustrate the embodiments of the present invention, some components in the attached drawings are omitted, enlarged or reduced, and do not represent the dimensions of actual products.

[0023] In the attached drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components; in the description of the present invention, it should be understood that if terms such as "upper", "lower", "left", "right", "inner", "outer", etc. are used to indicate the orientation or positional relationship, it is based on the orientation or positional relationship shown in the attached drawings. This is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the attached drawings are only for illustrative purposes and should not be construed as a limitation to this application. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0024] In the description of the present invention, unless otherwise clearly defined and limited, if terms such as "connection" are used to indicate the connection relationship between components, this term should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] Embodiment 1: The shortwave radio fax communication module provided in this embodiment is as Figures 1 - 25 shown, including: a central control unit, a storage unit, a user line interface circuit, an initialization module, a configuration module, a log module, a fax communication state machine module, a G3 fax machine fax communication module, a fax data encryption and decryption module, and a waveform protocol processing module; the central control unit is electrically connected to the storage unit, the user line interface circuit, and the embedded Modem respectively, and the initialization module, the configuration module, the log module, the fax communication state machine module, the G3 fax machine fax communication module, the fax data encryption and decryption module, and the waveform protocol processing module are stored in the Flash memory inside the central control unit in the form of software binary code; the module is connected to the G3 fax machine through a two-wire telephone line in a dedicated line or external line manner to realize the fax communication between the G3 fax machine and the shortwave radio. The fax data communicates with the waveform module according to the protocol. The module implements the LwIP protocol and the waveform module protocol, and the waveform module and the fax communication module use UDP transmission.

[0026] The shortwave radio fax communication module adopting the above technical solution connects each module through the central control unit, realizes the collaborative work among the modules, and constructs a complete shortwave radio fax communication system. By connecting to a G3 fax machine using a two-wire telephone line, fax communication between the G3 fax machine and the shortwave radio can be achieved, and communication is carried out using the LwIP protocol and the waveform module protocol, ensuring the reliability and stability of data transmission and providing the infrastructure for fax communication.

[0027] Specifically, in this embodiment, the storage unit includes a 1MB-capacity SRAM memory CY62157 and a 1MB Flash memory W25X80, which are used to store fax data, fax capability parsing information, and buffer data after encryption and decryption processing, and support on-demand dynamic allocation of up to 10 pages of fax data.

[0028] Adopting the above technical solution, the storage unit has a certain-capacity SRAM memory and Flash memory, which can effectively store fax data, fax capability parsing information, and buffer data after encryption and decryption processing. It supports on-demand dynamic allocation, can meet the storage requirements of different amounts of fax data, and ensures the flexibility and efficiency of data storage.

[0029] Specifically, in this embodiment, the user line interface is an SLIC circuit Ag1170, which is used for off-hook and on-hook signal detection, line feeding, and ring signal generation, supports dedicated line or external line connection methods for two-wire telephone lines, and is compatible with information security laser dedicated fax machines and shipboard secure fax machines of type G3 fax machines.

[0030] Adopting the above technical solution, the user line interface uses an SLIC circuit Ag1170, which can accurately detect off-hook and on-hook signals, feed the line, and generate ring signals. It supports multiple connection methods and is compatible with various types of G3 fax machines, enhancing the versatility and adaptability of the module and meeting the usage requirements of different users and different fax machines.

[0031] Specifically, in this embodiment, the fax communication state machine module realizes real-time scheduling of services such as PSTN fax communication, waveform protocol processing, off-hook and on-hook detection, dual-tone multi-frequency DTMF signal recognition, and ring signal generation through a state machine. After the system is powered on, it sequentially goes through the Initial state and the Idle monitoring state, and the state transition follows specific conditions and routes. Network reception is achieved through interrupt callbacks.

[0032] With the above technical solution, the fax communication state machine module realizes real-time scheduling of multiple services through the state machine, enabling the system to orderly process tasks such as PSTN fax communication, waveform protocol processing, and off-hook / on-hook detection. After the system is powered on, it runs according to specific state transition rules, and network reception is achieved through interrupt callbacks, improving the system's operation efficiency and response speed, and ensuring the smooth progress of various services.

[0033] Specifically, in this embodiment, the G3 fax machine fax communication module includes an embedded Modem MT9234, which communicates with the Modem through the internal UART of the central control unit, and realizes fax sending and fax receiving in accordance with the T.30 fax communication protocol. In the C stage of the T.30 fax protocol, software is used to monitor the (XON / XOFF) characters on the Modem line to achieve stop-and-wait flow control. The UART baud rate is set to 19200bps, and the line rate supports 9600bps or 11400bps. When receiving a fax, it is received by setting the UART to a baud rate of 57600bps and setting a large buffer, and no flow control is required. It realizes multiple limited-time response processes in the G3 fax machine call establishment, pre-message preparation process, and post-message release process, and reliably and completely receives and sends the fax encoded data frame in the message. The fax encoded data supports MH\MHR\MMR encoding methods.

[0034] With the above technical solution, the stop-and-wait flow control maintains the balance of data throughput between the Modem and the UART, realizes the complete and reliable sending and receiving of fax data messages, and the fax data messages support multiple encoding methods. Selecting an encoding method with a higher compression ratio is beneficial to shortening the fax message data transmission time on the short-wave channel.

[0035] Specifically, in this embodiment, the fax data encryption and decryption module encrypts and decrypts the fax image data, and uses the Blowfish symmetric block cipher algorithm with variable key length to encrypt and decrypt the fax page encoded data to ensure that the fax data transmitted by the radio cannot be deciphered, thereby improving communication security.

[0036] With the above technical solution, the fax data encryption and decryption module encrypts and decrypts the fax image data, and uses the Blowfish symmetric block cipher algorithm with variable key length to encrypt and decrypt the fax page encoded data, which can ensure that the fax data transmitted by the radio cannot be easily deciphered, greatly improving communication security and preventing fax information from being stolen or tampered with during transmission.

[0037] Specifically, in this embodiment, the waveform protocol processing module realizes protocol communication with the shortwave radio waveform module. The data packet format definition includes version, length, source module code, destination module code, type, checksum, and message payload. It uses the UDP protocol for transmission and has a data confirmation mechanism and a communication mechanism, which stipulate the waiting time and retransmission of data packets.

[0038] With the above technical solution, the waveform protocol processing module realizes protocol communication with the shortwave radio waveform module. Through a clear data packet format definition, it uses the UDP protocol for transmission and has a data confirmation mechanism and a communication mechanism, which stipulate the waiting time and retransmission of data packets, ensuring the accuracy and reliability of fax data during communication with the shortwave radio and reducing data loss and transmission errors.

[0039] Specifically, in this embodiment, the hardware part further includes the LM3S9B96 with the main controller ARMCortex-M3 core, the embedded Modem MT9234, the latch 7416373, the DTMF signal recognition circuit HT9172, and the power supply circuit. Each hardware component works together to provide hardware function support for the fax communication module.

[0040] With the above technical solution, each component of the hardware part works together. The main controller coordinates as the core, the embedded Modem realizes signal modulation and demodulation, the storage unit provides data storage functions for storing fax data and caching data for encryption and decryption processing, and auxiliary components such as the user line interface circuit, the DTMF signal recognition circuit, and the power supply circuit provide support, jointly providing stable hardware function support for the fax communication module and ensuring the normal operation of the entire module.

[0041] Specifically, in this embodiment, the software system includes the HAL hardware abstraction layer based on the circuit layer, the OS operating system layer, and the logical function application layer; the HAL hardware abstraction layer includes UART, Timer, GPIO, SRAM, FLASH, SLIC, and Modem driver programs; the logical function application layer includes PSTN calling sending, PSTN called receiving, state machine, waveform protocol transceiver processing module, initialization module, and fax data encryption and decryption module.

[0042] Specifically, in this embodiment, the initialization module performs power-on detection and initialization of system resources; the configuration module configures network parameters and line connection methods; the log module records the system activity status in real time and generates communication reports.

[0043] Specifically, in this embodiment, the PSTN calling party sending module adopts a stop-and-wait flow control method in the C stage of the T.30 facsimile communication protocol. The waveform protocol processing module uses a request-confirmation protocol-based flow control and retransmission error control method, ensuring efficient, reliable, and complete communication.

[0044] Specifically, in this embodiment, the waveform protocol processing module implements the LwIP protocol, and the waveform protocol is programmed and implemented in the way of Raw / Callback API callback, improving the performance of the system.

[0045] Adopting the above technical solution, the software system adopts a layered architecture, with clear division of labor for each layer. The HAL hardware abstraction layer provides hardware drivers, enabling upper-layer software to easily operate the hardware; the logical function application layer contains multiple functional modules, implementing various service logics of facsimile communication, improving the maintainability and scalability of the software, and facilitating system upgrade and optimization.

[0046] Embodiment 2: This embodiment provides a method for implementing shortwave radio facsimile communication, applying the shortwave radio facsimile communication module in Embodiment 1, including sending and receiving faxes. When sending a fax, the facsimile communication module receives the fax sent by the G3 fax machine, communicates and stores data through the T.30 facsimile communication protocol, encrypts it, and then transmits it to the service unit via the network for transmission by the shortwave radio. When receiving a fax, the shortwave radio sends the encrypted fax data to the facsimile communication module. After decryption, the fax sending process is initiated, and communication is carried out with the G3 receiving-end fax machine according to the T.30 facsimile communication protocol.

[0047] This method details the processes of sending and receiving faxes, realizes facsimile communication between the G3 fax machine and the shortwave radio, ensures accurate and secure transmission of fax data between different devices, and solves the problems existing in the existing shortwave radio facsimile communication.

[0048] Among them, when sending a fax, when configured in the external line mode, the calling G3 fax machine picks up the phone and dials *# to start the receiving process, and sends it by pressing the start button according to the call establishment A stage of the T.30 facsimile communication protocol; when configured in the dedicated line mode, the G3 fax machine directly connects and receives the fax message after pressing the start button. When receiving a fax, in the external line mode, the line off-hook / on-hook status is detected, and a ringing signal is sent to notify the receiving party to pick up the phone. In the dedicated line mode, the line is always off-hook, and an attempt is directly made to connect in the A stage. After successful connection, communication is carried out according to the T.30 facsimile communication protocol. For different configuration methods (external line mode and dedicated line mode), specific operation processes for sending and receiving faxes are given respectively, enabling the module to better adapt to different usage scenarios, improving the flexibility and compatibility of the system, and meeting diverse user needs.

[0049] In summary, the shortwave radio facsimile communication module provided in this embodiment has the following advantages: Through the collaborative work of each module, the shortwave radio fax communication module in this embodiment realizes dedicated line or external line connection with a G3 fax machine, supports multiple fax coding methods, encrypts and decrypts fax data, and improves communication security; it realizes real-time scheduling of services through a state machine, ensuring the efficient and reliable operation of the system. The method for realizing shortwave radio fax communication details the processes of sending and receiving faxes, is compatible with different configuration methods, solves the problems in the prior art, and is applicable to fields such as emergency communication, maritime communication, and military communication.

[0050] The shortwave radio fax communication module provided in this embodiment mainly consists of module hardware and a software system, where: Composition of module hardware The main controller, LM3S9B96 with an ARM Cortex-M3 core, serves as the central control unit to coordinate the work of each hardware component. The embedded Modem MT9234 realizes signal modulation and demodulation, and the SLIC circuit Ag1170 serves as the user line interface to detect off-hook and on-hook signals, provide line feeding, and generate ring signals. The DTMF signal recognition circuit HT9172 recognizes dual-tone multi-frequency signals. The SRAM memory CY62157, Flash memory W25X80, and latch 7416373 form a storage system to store data related to fax messages. Auxiliary components such as the power supply circuit ensure the stable operation of the hardware system.

[0051] Operation of the software system After the system is powered on, initialization is completed in the Initial state. If the initialization is successful, it enters the Idle monitoring state. In the Idle state, it monitors the off-hook signal or network received data. When a fax machine off-hook is detected, it determines whether to enter the voice call state or the PSTN fax receiving state by the number dialed through the DTMF signal recognition circuit. In the PSTN fax receiving state, it receives fax data according to the T.30 fax communication protocol, stores and encrypts it, and starts the network sending process. After the network sending is completed, it reports the status and returns to the Idle state. When receiving a fax, it receives data from the waveform module, decrypts it, and sends it to the G3 fax machine according to the T.30 fax communication protocol. The entire process is scheduled in real time by the fax communication state machine module.

[0052] Working principle process: The overall working principle process of this shortwave radio fax communication module is divided into two main processes: sending a fax and receiving a fax: Sending a fax 1. Connection and Data Reception: The G3 fax machine is connected to the fax communication module via a two-wire telephone line in a dedicated line or outside line mode. If configured in the outside line mode, the calling G3 fax machine picks up the phone and dials *# to start the reception process, and sends it by pressing the start button in Phase A of the call establishment of the T.30 fax communication protocol; if in the dedicated line mode, the G3 fax machine directly connects and receives the fax message after pressing the start button. The fax communication module receives the fax data sent by the G3 fax machine through the user line interface.

[0053] 2. Data Storage and Processing: The received fax data is stored in the storage system, and at the same time, the fax communication state machine module analyzes the fax capabilities. The fax data encryption and decryption module encrypts the data to ensure data security.

[0054] 3. Data Transmission: The encrypted fax data is processed by the waveform protocol processing module and is transmitted over the network using the UDP protocol according to the protocol communication rules with the shortwave radio waveform module, and is sent to the service unit, and finally transmitted by the shortwave radio.

[0055] Receiving a Fax 1. Data Reception: The shortwave radio sends the received encrypted fax data to the fax communication module, and the waveform protocol processing module receives the data.

[0056] 2. Data Decryption: The fax data encryption and decryption module decrypts the encrypted fax data to restore the original fax data.

[0057] 3. Data Sending and Communication: After the fax data decryption is completed, the fax sending process is started. The fax communication module communicates with the G3 receiving fax machine according to the T.30 fax communication protocol. In the outside line mode, the line off-hook and on-hook status is detected, and a ringing signal is sent to notify the receiving party to pick up the phone; in the dedicated line mode, the line is always off-hook, and an attempt is directly made to connect in Phase A. After the connection is successful, the fax data is sent to the G3 receiving fax machine.

[0058] Throughout the process, the central control unit coordinates the work of each module, and the fax communication state machine module schedules various services in real time through the state machine to ensure the efficiency, accuracy and security of fax communication.

[0059] Condition 1: The off-hook signal is detected, and *# is received through the DTMF signal recognition circuit, and the circuit is blocked, indicating that the line is busy. If a fax machine picks up the phone at this time, a busy tone is prompted and a busy tone signal is returned. When Condition 1 is met, it enters the PSTN fax receiving state and completes the PSTN fax receiving process. If the receiving process is abnormally terminated or an error occurs, it enters the Idle state.

[0060] Condition 2: If the PSTN receiving process is successfully completed, the network fax transmission can be initiated. That is, the condition is that the PSTN receiving process is successfully completed (i.e., PSTN receiving is OK), and it enters the network fax transmission state. After completing the network fax transmission process, the process is abnormally terminated or successfully completed and transferred to the Idle monitoring state.

[0061] Condition 3: The network fax transmission process is abnormally terminated or successfully completed and transferred to the Idle monitoring state.

[0062] Condition 4: The off-hook signal is detected, and the digital number is received through the DTMF signal recognition circuit, and a voice link is established to enter the service unit (shortwave module), that is, the physical connection is established. The voice channel is provided by the shortwave module. When Condition 4 is met, it enters the voice call state.

[0063] Condition 5: Data reception is detected on the network port, and the message content is a request to send (valid) and line configuration, handshake message, indicating that there is subsequent data transmission, that is, a connection is established, and after successful handshake, a large amount of data can be received through the network.

[0064] Condition 6: If the initialization is OK, it is transferred to the Idle monitoring state. If the initialization fails (FAIL), it enters the abnormal error state.

[0065] Condition 7: If the receiving process is abnormally terminated or an error occurs. It is transferred from the PSTN fax receiving state to the Idle monitoring state.

[0066] Condition 8: The PSTN fax transmission is normal or abnormally ended, and it is transferred to the Idle monitoring state.

[0067] Condition 9: The error exception handling is completed, that is, the exception or error is repaired, and it is transferred to the Idle monitoring state. For serious exceptions, the system is automatically restarted through the watchdog circuit.

[0068] Condition 10: If a hardware or software error or problem occurs in the Idle monitoring state, it enters the abnormal error state.

[0069] Condition 11: If the network receives the fax OK (normally ended), the PSTN fax transmission process (flow) is automatically initiated. The condition is that the network reception is OK.

[0070] Condition 12: After the voice call is completed, it enters the Idle monitoring state.

[0071] Condition 13: The network reception is abnormally terminated or an error occurs. It is transferred from the network fax receiving state to the Idle monitoring state.

[0072] The above are only the preferred embodiments of the present invention, and do not limit the implementation manners and protection scope of the present invention thereby. For those skilled in the art, it should be realized that all the solutions obtained by equivalent substitution and obvious changes made by using the specification and illustrated content of the present invention should be included within the protection scope of the present invention.

Claims

1. A shortwave radio fax communication module, characterized in that, It includes: A central control unit, a storage unit, a user line interface circuit, an initialization module, a configuration module, a log module, a fax communication state machine module, a G3 fax machine fax communication module, a fax data encryption and decryption module, and a waveform protocol processing module; the central control unit is electrically connected to the storage unit, the user line interface circuit, and the embedded Modem respectively; the initialization module, the configuration module, the log module, the fax communication state machine module, the G3 fax machine fax communication module, the fax data encryption and decryption module, and the waveform protocol processing module are stored in the Flash memory inside the central control unit in the form of software binary code; the module is connected to the G3 fax machine through a two-wire telephone line in a dedicated line or external line manner to realize the fax communication between the G3 fax machine and the shortwave radio station. The fax data communicates with the waveform module according to the protocol. The module implements the LwIP protocol and the waveform module protocol, and the waveform module and the fax communication module use UDP transmission.

2. The short-wave radio fax communication module according to claim 1, characterized in that The storage unit includes a 1MB-capacity SRAM memory CY62157 and a 1MB Flash memory W25X80, which are used to store fax data, fax capability parsing information, and buffer data after encryption and decryption processing, and support on-demand dynamic allocation of up to 10 pages of fax data.

3. The shortwave radio fax communication module according to claim 1, characterized in that, The user line interface circuit is an SLIC circuit Ag1170, which is used for off-hook and on-hook signal detection, line feeding, and ring signal generation, supports dedicated line or external line connection methods of two-wire telephone lines, and is compatible with information security laser dedicated fax machines and shipboard secure fax machines of type G3 fax machines.

4. The shortwave radio fax communication module according to claim 1, characterized in that, The fax communication state machine module realizes the real-time scheduling of PSTN fax communication, waveform protocol processing, off-hook and on-hook detection, dual-tone multi-frequency DTMF signal recognition, and ring signal generation services through a state machine. After the system is powered on, it successively experiences the Initial state and the Idle monitoring state. The state transition complies with specific conditions and routes, and network reception is realized through interrupt callbacks.

5. The shortwave radio fax communication module according to claim 1, characterized in that, The G3 fax machine fax communication module includes an embedded Modem MT9234, which communicates with the Modem through the internal UART of the central control unit, and realizes fax sending and fax receiving according to the T.30 fax communication protocol. In the C stage of the T.30 fax protocol, a stop-and-wait flow control mechanism is adopted to solve the complete and reliable transmission of the entire fax data frame. The stop-and-wait flow control is realized by monitoring the XON / XOFF characters on the Modem line through software. The UART baud rate is set to 19200bps, and the line rate supports 9600bps or 11400bps. When receiving a fax, the UART is set to 57600bps baud rate for reception, and a large buffer is set to avoid the need for flow control, so as to realize multiple limited-time response processes in the call establishment, pre-message preparation process, and post-message release process of the G3 fax machine, and the reliable and complete reception and transmission of the fax encoded data frame in the message. The fax encoded data supports MH\MHR\MMR encoding methods.

6. The shortwave radio fax communication module according to claim 1, characterized in that The fax data encryption and decryption module encrypts and decrypts fax image data. It uses the Blowfish symmetric block cipher algorithm with variable key length to encrypt and decrypt fax page encoding data, ensuring that the fax data transmitted by the radio cannot be deciphered and improving communication security.

7. The shortwave radio fax communication module according to claim 1, characterized in that, The waveform protocol processing module realizes protocol communication with the shortwave radio waveform module. The data packet format definition includes version, length, source module encoding, destination module encoding, type, checksum, and message payload. It uses the UDP protocol for transmission and has a data confirmation mechanism and communication mechanism, which stipulate the waiting time and retransmission of data packets.

8. The shortwave radio fax communication module according to claim 1, characterized in that The hardware part also includes LM3S9B96 with an ARMCortex-M3 kernel as the main controller, embedded Modem MT9234, latch 7416373, DTMF signal recognition circuit HT9172, and power supply circuit. Each hardware component works together to provide hardware function support for the fax communication module.

9. The shortwave radio fax communication module according to claim 1, characterized in that, The software system includes the HAL hardware abstraction layer based on the circuit layer, the OS operating system layer, and the logical function application layer. The HAL hardware abstraction layer includes UART, Timer, GPIO, SRAM, FLASH, SLIC, and Modem driver. The logical function application layer includes an initialization module, a state machine, a fax data encryption and decryption module, a configuration module, a log module, a PSTN calling sending module, a PSTN called receiving module, and a waveform protocol transceiver processing module.

10. The shortwave radio fax communication module according to claim 1, wherein The simulation debugging software supports waveform protocol transceiver communication. It can conveniently receive and send fax data through the network, and can view fax image data in the form of Tiff files. The data display window displays communication data in real time.

11. The shortwave radio fax communication module according to claim 1, characterized in that, The initialization module performs power-on detection and initialization of system resources. The configuration module configures network parameters and line connection methods. The log module records the system activity status in real time and generates communication reports.

12. The shortwave radio fax communication module according to claim 1, characterized in that The PSTN calling sending module uses the stop-and-wait flow control method in phase C of the T.30 fax communication protocol. The waveform protocol processing module uses the request-confirmation protocol-based flow control and retransmission error control method.

13. The short-wave radio fax communication module according to claim 1, wherein, The waveform protocol processing module implements the LwIP protocol, and the waveform protocol is programmed and implemented in the way of Raw / CallbackAPI callback.

14. A method for realizing facsimile communication of a short-wave radio, applying the short-wave radio facsimile communication module according to any one of claims 1-13, characterized in that, It includes sending faxes and receiving faxes. When sending a fax, the fax communication module receives the fax sent by the G3 fax machine, communicates through the T.30 fax communication protocol and stores the fax page encoding data. After encryption processing, it is transmitted to the service unit through the network and sent by the shortwave radio. When receiving a fax, the shortwave radio sends the encrypted fax data to the fax communication module. After decryption, it starts the fax sending process and communicates with the G3 receiving-end fax machine according to the T.30 fax communication protocol.

15. The method for implementing short-wave radio facsimile communication according to claim 14, wherein, When sending a fax, when configured in the external line mode, the calling G3 fax machine picks up the phone and dials *# to start the receiving process, and sends it by pressing the start button according to the call establishment phase A of the T.30 fax communication protocol; when configured in the dedicated line mode, the G3 fax machine directly connects and receives the fax message after pressing the start button; when receiving a fax, in the external line mode, the line off-hook / on-hook status is detected, and a ringing signal is sent to notify the receiving party to pick up the phone. In the dedicated line mode, the line is always off-hook, and an attempt is directly made to connect in phase A. After the connection is successful, communication is carried out according to the T.30 fax communication protocol.

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