Abstract: Voice cards play a crucial role in computer telephony integration technology and are a core component of voice technology. To improve the efficiency of airport pipeline refueling systems and reduce input errors, an automatic control system based on voice technology was developed. The feasibility and reliability of this technology were practically verified through its application in an airport pipeline refueling project. First, the general functions of the voice card and the airport pipeline refueling automation system are described. Then, based on this, the underlying hardware configuration of the system and the hardware system built using the voice card are introduced. Finally, the successful application of voice technology implemented through software programming in the airport pipeline refueling automatic control system is introduced. Keywords: Voice card, pipeline refueling, automatic control. Currently, many airport pipeline refueling systems face challenges in equipment modification and the application of automatic control technology. We have developed an automated system for airport pipeline refueling using voice technology and successfully applied it in engineering practice. In the airport pipeline refueling automation system, the application of voice technology helps operators correctly input relevant information using the equipment according to normal procedures, smoothly completing the refueling operation. Compared with other input methods, voice technology achieves "foolproof" operation, ensuring the correctness and completeness of input information, reducing the labor intensity of operators while improving work efficiency and refueling capacity. I. General Functions of a Voice Card A voice card, also known as a voice board, is an expansion card for industry-standard compatible computers, enabling voice processing functions. There are many types of voice cards, including analog voice processing cards, digital trunk interface voice cards, fax cards, agent transfer cards, conference function cards, voice recognition cards, etc. Telephone voice cards are one of the core components in the field of "Computer Telephone Integration Technology (CTI)," and their development has always been closely related to the widespread application of voice technology and the advancement of computer technology. In this project, the TW8VID analog telephone voice card from Beijing Wuyuexin Information Technology Co., Ltd. was selected. This telephone voice card has eight independent channels. Combined with different modules, it can function as an internal or external line. Each channel can be programmed by software to perform the following basic functions: 1. Automatically detect the ringing signal when an external caller calls and the on/off actions of an internal caller; 2. Control the on/off actions of external calls and the power supply or ringing of internal calls; 3. Digitize and play back voice messages using PCM or ADPCM encoding to create computer voice files; 4. Send the digitized computer voice files to the telephone line; 5. Receive user telephone keypad signals (DTMF), supporting both FSK and DTMF caller ID formats; 6. Detect polarity reversal signals during recording and playback; 7. Accurately receive caller IDs from the exchange; 8. Implement the functions of a programmable controller; 9. Utilize different modules to implement functions such as human agent support and simultaneous recording; 10. Form a voice/fax system with a fax card and a telephone conferencing system with a conference card; 11. Supports up to 16 voice cards in a single unit, enabling non-blocking switching between 128 lines. 12. Other functions, such as inter-channel communication and adjustable voice compression ratio. Based on system requirements, the software for this automated system primarily utilizes the first six functions when programming the voice card: detecting the on/off status of the explosion-proof telephone; controlling the on/off status of the field telephone and ringing it as needed; recording multiple independent prompt voice message files; transmitting the prompt voice files to the corresponding explosion-proof telephone according to a predetermined program; receiving key input from the user on the explosion-proof telephone, etc. II. General Functions of Airport Pipeline Refueling Automation Systems From the current status of airport pipeline refueling automation systems under development or in use, their main functions include the following: 1. Tank Level Detection: Tank level detection is generally accomplished through a level sensor connected to a computer. The tank level signal can be displayed on-site or amplified and transmitted remotely to the computer in the central control room for display and recording. The tank level signal helps managers observe changes in the tank's fuel level, adjust tank usage promptly, and prevent overflow during refueling and empty tanks during refueling. 2. Oil Pump Motor and Valve Control: Oil pumps in the pump room are typically controlled using variable frequency speed regulation. When there are many refueling ports and a large oil flow rate, the oil pump motor rotates at high speed to output greater power, increasing the oil flow rate to meet requirements; when there are few refueling ports and a small oil flow rate, the oil pump motor rotates at low speed, reducing the oil flow rate. In airport pipeline refueling automation systems, some valves requiring automatic control are generally electric or electro-hydraulic valves. A remote computer outputs control signals to control the opening and closing of these valves to connect or disconnect the oil passage. 3. Refueling Quantity Control: Pipeline refueling automation systems commonly use flow meters with transmitters. These can display the refueling quantity locally and output instantaneous or cumulative flow information during the refueling process in different formats and signal types. This information is amplified and transmitted remotely to the computer, thus enabling the software system to control the refueling quantity. There are generally two methods: quantitative refueling and non-quantitative refueling. The choice between these two methods depends on the system requirements. Quantitative refueling is normally used to reduce workload, but non-quantitative refueling can be implemented in special circumstances to prevent data loss and oil waste. 4. Remote input of refueling information can be achieved through various input technologies, such as keyboard input, IC card technology, and barcode technology. The advantages and disadvantages of different input methods will not be discussed here. The automated system described in this article uses keyboard input technology combined with voice technology. Users input the refueling operator's code, password, receiving equipment code, and refueling quantity via the explosion-proof telephone at the refueling terminal. The control computer receives, identifies, records, and stores this data for use by the management information system. 5. Refueling data reception: The temperature and pressure of the fuel are provided by temperature and pressure sensors installed on the pipeline; the refueling time is automatically collected and recorded by the computer; the refueling location is represented by different identifiers on the input devices installed at the refueling terminal; the volume of fuel refueling is directly given by the flow meter, and the mass of fuel refueled is obtained by multiplying the volume by the density corresponding to the fuel temperature. This information is acquired and verified through different devices, enabling automatic collection and storage of refueling data to facilitate the coordinated operation of the entire system. 6. Management Information System: A management information system is established to comprehensively manage fuel storage, receipt, dispatch, consumption, and daily, monthly, and quarterly reports. It automatically processes fuel data, enabling various categories of fuel information queries and management, and generating and printing reports. After connecting to the fuel system's computer network, fuel information can be transmitted and shared remotely, facilitating higher-level management's review and verification of the unit's fuel accounts. III. Hardware Design of an Airport Pipeline Refueling Automation System Based on Voice Technology In this airport pipeline refueling automation system, the data to be collected generally includes refueling quantity, fuel temperature, fuel pressure, refueling time, refueling location, and refueling operation information. The flow meter emits pulse signals, which are converted to obtain the volume of fuel being refueled; the temperature sensor emits analog signals, which are converted to obtain fuel temperature information, allowing automatic calculation of the fuel weight from the refueling volume; the pressure sensor emits analog signals to represent pressure changes in the pipeline system; different input device identifiers represent different refueling locations; refueling time and operation information can be automatically obtained and fed back by the computer through a voice card and input devices. The flow of oil in the pipeline system is automatically controlled by a computer that sends digital signals through programmed software to drive the opening and closing of electric valves. Under the premise of meeting the above hardware requirements, the structure of the airport pipeline refueling automation system implemented in this project is shown in Figure 1. Temperature and pressure sensors are installed in the oil pump room, while flow meters, electric valves (here, electro-hydraulic valves are selected), and explosion-proof telephones are installed at different refueling terminals and assigned different identification codes. [align=center] Figure 1: Block Diagram of Airport Pipeline Refueling Automation System[/align] Based on the principles of system integration, a Kangtuo industrial control computer (Advantech motherboard) and its industrial-grade boards are selected to construct the airport pipeline refueling automation system, and its hardware connection is shown in Figure 2. According to the actual needs of the project, the following I/O signal types are present on-site: pulse signals output from the flow meter, analog signals output from the pressure and temperature sensors, digital signals input for controlling the opening and closing of the electro-hydraulic valves, DTMF signals output from the explosion-proof telephones, etc. Among these, the DTMF signals need to be received and recognized through a voice card, and the computer prompt voice files also need to be transmitted to the explosion-proof telephones through the voice card to produce sound. [align=center]Figure 2 Hardware Connection Diagram of Airport Pipeline Refueling Automation System[/align] In constructing this hardware system, some terminal blocks and conditioning circuits were self-made. The signal processing was tested and successfully applied to a practical project. To support the software development of the voice card, numerous experiments were conducted to clarify the ASCII codes corresponding to the output information of each key on the explosion-proof telephone after being received by the voice card, and its signal transmission anti-interference capability was tested. IV. Application of Voice Technology in the Airport Pipeline Refueling Automation System According to the user's requirements, the functional analysis, scheme design, and user consultation of the airport pipeline refueling automation system software were carefully completed. In-depth communication and discussion were conducted with the user on key technical issues in the system, and a consensus was finally reached. The system software was developed using Delphi 5.0, employing object-oriented technology and modular design to maintain good inheritance, extensibility, and maintainability, leaving room for expansion when conditions permit. This software design includes an entry form, a password change form, a refueling system monitoring form, an information management form, and an exit form. The input, reception, and feedback of refueling operation information are completed using explosion-proof telephones and voice cards. The TW8VID voice card has internal modules configured on all eight channels, connecting to the eight refueling ports of the refueling system. Each refueling port is equipped with an explosion-proof telephone for inputting refueling information and receiving prompt voice messages from the system to guide the user through the next step. The output prompt voice messages are pre-recorded via telephone, forming computer voice files that are stored for later retrieval. The voice technology in this system primarily performs the following functions: 1. The system initializes each channel of the voice card and monitors whether each channel is off-hook. 2. When the system detects that a channel is off-hook, an airplane icon is displayed on the corresponding refueling port on the refueling system monitoring window, and the prompt "Please enter the refueling operator's code, press # to end" is output. 3. After the user enters the refueling operator's code, the system checks if this code exists in the database. If it does not exist, the user is prompted to re-enter it. If it exists, the system prompts the user to enter the refueling operator's password. 4. After the user enters the refueling operator's password, the system checks the database to see if this password matches the password corresponding to the aforementioned code. If the input doesn't match, the system prompts the user to re-enter the information. After three invalid attempts, the channel is set to standby mode. If the input matches, the system prompts the user to enter the receiving equipment code. 5. After the user enters the receiving equipment code, the system checks if the code exists in the database. If not, the user is prompted to re-enter the information. If the code exists, the system displays the receiving equipment code on the window and prompts the user to enter the refueling quantity. 6. After the user enters the refueling quantity, the system checks if it is less than the maximum refueling quantity for this equipment. If it is greater than the maximum, the user is prompted to re-enter the information to prevent overflow during refueling. Otherwise, the system prompts "Refueling begins now. Please hang up after refueling is complete," and simultaneously outputs an open signal to the corresponding electro-hydraulic valve to open the valve and begin refueling. 7. The system displays the preset refueling quantity on the window and displays the converted real-time refueling quantity based on the pulse signal output by the flow meter. During refueling, if the user hangs up when the real-time refueling quantity is less than the preset quantity, the system stores the real-time refueling quantity in the database and outputs a signal to close the electro-hydraulic valve. This situation is considered indefinite refueling. If the user does not intervene during refueling, the system will automatically output a signal to close the electro-hydraulic valve when the real-time refueling volume equals the preset refueling volume, stopping refueling and storing the refueling volume in the database. This is called quantitative refueling. 8. After the system is connected, set this channel to standby mode. The analog signals output by the pressure sensor and temperature sensor are converted and displayed on the refueling system monitoring window to help the administrator determine whether the refueling system is working properly. Each time refueling data is stored, information such as the fuel temperature, refueling location, and refueling time measured by the system is stored in the database for convenient refueling information management. After the installation of the automated pipeline refueling system at this airport was completed, a series of debugging tests were conducted on the hardware and software systems, and software usage training was provided to operators and managers to ensure they mastered the system's usage methods and precautions. Based on this, actual refueling drills were conducted. The user tested the system's hardware and software according to the design scheme and experimented with the reliability and accuracy of the data, finally successfully completing the acceptance test. After the system has been running for a period of time, the information returned by the user indicates that the hardware is reliable, the software functions are complete, the information transmission is stable, and the data is accurate and complete. The application of voice technology in airport pipeline refueling automation systems has improved operator efficiency, reduced new employee training time, and significantly enhanced the overall system's fuel supply capacity, making it a distinctive feature and highlight. V. Conclusion After the development of the voice technology-based airport pipeline refueling automation system, it has been installed and used in multiple airports. Practical application shows that this is a simple, reliable, and economical technical solution with advantages such as user-friendly design, intuitive operation, and stable data transmission. It greatly reduces the labor intensity of personnel, improves labor productivity and unit economic benefits, and has received widespread praise from users. The authors' innovations include: firstly proposing the application of voice technology in airport pipeline refueling automation systems and successfully putting it into practice; and designing voice technology application steps and prompts suitable for pipeline refueling systems.