Subway broadcasting intercom

System Overview

The subway broadcast intercom system is a professional communication solution specifically designed for the subway environment. It integrates multiple key functions such as emergency communication, daily operation coordination, security management, and passenger service. The core objective of this system is to achieve efficient and reliable voice communication in the complex subway environment to handle various routine and emergency situations.

The main functions of the system include:

• Emergency Communication: Provide stable and reliable communication guarantee during emergencies.
• Daily Operation Coordination: Improve the efficiency and service quality of subway operations.
• Security Management: Assist security personnel in effective monitoring and incident handling.
• Passenger Service: Provide convenient information consultation services for passengers.

Through these functions, the system significantly enhances the safety, operational efficiency, and passenger satisfaction of the subway, playing an indispensable role in subway operation management.

System Components

The subway broadcast intercom system is a highly integrated communication solution consisting of multiple key components to ensure efficient and reliable voice communication in the complex subway environment. The system mainly includes the following core components:
Central Control Console
Serving as the nerve center of the system, it is responsible for coordinating and managing the communication activities of the entire network. It is usually equipped with an advanced touch-screen interface, which is simple and intuitive to operate. There are multiple function buttons on the console, such as one-touch calling and all-zone broadcasting, facilitating the quick initiation of various services. In addition, the console also integrates a recording function that can automatically record important call contents, providing a basis for subsequent analysis and evidence collection.
On-board Equipment
Installed on subway trains, it mainly includes the on-board broadcast host and speakers in the carriages. The on-board broadcast host is responsible for receiving instructions and information from the central control console and broadcasting them to passengers through the speakers. Modern systems also support the automatic station announcement function, which achieves precise station announcements through GPS positioning and preset programs.
Station Terminals
Usually deployed in crowded areas such as platforms and ticket halls. These terminals integrate intercom and broadcasting functions, allowing staff to have real-time conversations with the central control console or other terminals and also used to play pre-recorded broadcast information. Some advanced systems are also equipped with LCD displays that can show text information and video images, further enriching the ways of information transmission.
Network Infrastructure
Including devices such as switches, routers, and wireless access points, it forms the backbone network of the system. These devices are interconnected by wired and wireless means, creating a communication matrix covering the entire subway network. It is particularly worth mentioning that the system adopts advanced wireless communication technologies, such as digital trunking or LTE, to ensure signal coverage and communication quality in the special subway environment.
Software Modules
Mainly including operating systems, database management systems, and application programs. These software are responsible for processing voice signals, managing user permissions, storing communication records, and other key tasks. In particular, the audio processing module adopts advanced audio compression and noise reduction algorithms to ensure the call quality in the noisy subway environment.
Through the organic combination of these carefully designed hardware and software components, the subway broadcast intercom system achieves comprehensive coverage, efficient and reliable, and functionally rich communication services, providing strong support for subway operations.

System Functions

1. Passenger Service Aspects

   • Train Information Broadcasting: Broadcast real-time information about the arrival and departure of trains. For example, when a train is about to enter the station, the SIP broadcast intercom system in the platform area will broadcast, "The train heading for [terminal station] is about to enter the station. Please wait behind the safety line, passengers." After the train departs, it will broadcast the estimated arrival time of the next train, facilitating passengers to reasonably arrange their trips. In case of special situations such as train delays, it will promptly convey the delay reasons and the estimated time to resume normal operation to passengers to soothe their emotions.
   • Station Guidance Broadcasting: Provide guidance for passengers in complex passages, transfer areas and other places within the subway station. For example, in a transfer station, it will broadcast, "Passengers going to [line name], please follow the indication signs to the transfer passage", which helps passengers successfully find the transfer route and reduces the situations of getting lost and taking the wrong train. It also guides passengers to the service facilities within the station, such as broadcasting contents like "Passengers who need to use the restroom can go to [specific direction]", thus enhancing passengers' travel experience.
   • Emergency Notification: In the event of emergencies such as fires, terrorist attacks or earthquakes, the SIP broadcast intercom system can quickly broadcast emergency evacuation instructions to the whole station or specific areas. For example, it will broadcast, "An emergency situation has occurred in the station. Please remain calm, passengers, and evacuate in an orderly manner according to the evacuation signs towards [evaculation direction]." In case of special situations such as platform screen door failures, it will broadcast instructions to passengers, such as "The platform screen door has malfunctioned. Please pay attention to safety, passengers, and stay away from the faulty screen door."

   • Operation Management Aspects

     • Departmental Communication and Collaboration: There are multiple departments in a subway station, such as ticketing, station affairs, equipment maintenance, and dispatching. The SIP broadcast intercom system facilitates instant communication between different departments. For example, if the ticketing department discovers that a ticket vending machine has malfunctioned, it can notify the equipment maintenance department through the intercom system; if station staff notice an abnormal situation on the platform, they can promptly communicate with the dispatching center and obtain instructions. Different departments can set up different intercom groups to improve communication efficiency and reduce unnecessary interference. For example, all platform staff can be grouped into one group, and all equipment maintenance staff can be grouped into another group.
     • Equipment Maintenance and Dispatching: There are a large number of devices in a subway station, such as automatic ticket vending machines, elevators, escalators, and ventilation equipment. When a device malfunctions, the sensors on the device can be linked with the SIP broadcast intercom system to send fault alarm information to the maintenance staff. The maintenance staff can receive tasks through the system and be dispatched to the fault site. During the maintenance process, they can maintain contact with the control center to obtain technical support or coordinate resources, such as coordinating with the power department when power outage maintenance is required.
     • Personnel Dispatching and Management: Operation management personnel can use the SIP broadcast intercom system to dispatch staff. During peak hours, more station staff can be dispatched to crowded areas such as platforms and ticket gates to maintain order; in case of special situations such as train delays, they can direct staff to conduct passenger flow guidance work. Through the system, real-time work arrangements and task assignments can be made for staff, such as notifying staff to conduct cleaning work or facility inspection work in specific areas.

   • Security and Protection Aspects

     • Security Monitoring and Command: When patrol personnel discover abnormal situations, such as illegal border-crossing behaviors, they can quickly report to the command center through the intercom function and communicate and cooperate with nearby patrol personnel to take measures such as encirclement.

Technical Principles

Communication Technologies

The subway broadcast intercom system adopts a series of advanced wireless communication technologies to ensure efficient and reliable voice communication in the complex subway environment. The selection and application of these technologies fully reflect the profound understanding of the characteristics of the subway environment and the accurate grasp of communication requirements by the system designers.
The core technologies of the system include:

The comprehensive application of these technologies not only improves the communication quality and stability but also provides more diversified services for subway operations. For example, the application of LTE technology enables the system to support high-definition video calls and real-time data transmission, greatly enhancing the safety and efficiency of subway operations.
It is worth noting that the system also adopts measures such as multi-antenna technology and tunnel distribution systems to further improve the coverage ability of the subway vehicle-ground wireless communication network. These measures effectively solve the signal propagation problems specific to the subway environment, such as severe signal attenuation in tunnels, ensuring the stability and coverage range of signals.
Through the comprehensive application of these advanced technologies, the subway broadcast intercom system can achieve high-quality and highly reliable voice communication in the complex subway environment, providing strong communication guarantee for subway operations.
Audio Processing
In the subway broadcast intercom system, audio processing technology plays a crucial role in ensuring high-quality voice communication. The system adopts advanced audio compression and noise reduction algorithms to cope with the complex noise conditions in the subway environment. Among them, the Active Noise Cancellation Technology (ANC) is particularly prominent. It cancels background noise by generating sound waves with opposite phases to the ambient noise, significantly improving voice clarity.
At the same time, the system also integrates a Digital Vocoder, which is responsible for converting analog voice signals into digital signals and performing compression coding, ensuring both sound quality and transmission efficiency. The comprehensive application of these technologies ensures the good performance of the system in the subway environment, providing users with a clear and reliable voice communication experience.

Network Architecture

The subway broadcast intercom system adopts an advanced network architecture to ensure efficient and reliable voice communication in the complex subway environment. This architecture makes full use of the existing communication infrastructure and introduces some innovative technologies to meet the unique needs of the subway environment.
The core network architecture of the system is based on XPT (Extended Pseudo Trunking) technology, which is a distributed cluster system. One of the显著特点 of the XPT system is its flexible channel resource allocation mechanism. When a channel is busy, the intercom users in the XPT system can share the idle channels in the station instead of being fixed to a specific channel. This mechanism allows users to maximize the expansion of system capacity without increasing costs and effectively utilize the existing channel resources.
The network topology of the XPT system usually includes the following components:

• Terminal: Intercoms and other communication devices
• Repeater: Responsible for signal forwarding and management
• Ethernet Switch: Connects each repeater and server
• Router: Implements wide area network connection
• IPPBX: Connects the telephone system
• Third-party Applications: Such as dispatching systems, network management systems, etc.

In the XPT system, the Repeater plays a crucial role. A single XPT station system consists of a main repeater and multiple subordinate repeaters. Terminals will be assigned dedicated frequencies and time slots in advance. When the terminal is idle, it will monitor its main repeater in real time. The main repeater broadcasts XPT system status information on each frequency through test signals, informing the terminals which channels are available and whether there are calls. This mechanism ensures that the terminals can quickly and accurately jump to the appropriate channels and time slots for communication.
To expand the communication coverage area, the XPT system also supports the Multi-station Cluster architecture. By connecting multiple XPT single-station systems through an IP network, an IP-interconnected digital repeater system, namely the XPT multi-station cluster system, can be formed. This architecture not only ensures the channel resource sharing characteristics of the XPT single-station cluster system but also expands the communication coverage area of the XPT system.
In terms of data transmission, the XPT system adopts the "Request and ｇｒａｎｔ" mechanism to allocate channels. Before initiating a call, the intercom will first perform a handshake confirmation with the repeater to ensure that the call can be successfully connected to an effective service channel. This mechanism effectively prevents the situation where the intercom stays on the wrong channel due to call conflicts and also avoids the interference caused by a strong-signal intercom to other users using the same channel.
The design of this network architecture fully considers the special needs of the subway environment, such as signal coverage range and anti-interference ability. By adopting the XPT technology, the system can ensure communication quality while maximizing the utilization of existing resources, providing efficient and reliable communication guarantee for subway operations.

Application Scenarios

Daily Operations

The subway broadcast intercom system plays a vital role in daily operations, especially in train operation and platform management. This section will introduce in detail the specific applications and benefits of the system in these two key scenarios.
Train Operation
One of the core functions of the system is Automatic Station Announcement. Through advanced GPS positioning technology and preset programs, the system can achieve precise station announcements. This not only reduces the workload of drivers but also ensures that passengers can timely and accurately understand the travel information. For example, if a passenger is taking the subway to the airport to catch a flight, the accurate automatic station announcement function can help him better plan the time and transfer, avoiding missing the destination station.
Platform Management
The system also plays an important role. Staff can maintain contact with the control center at any time through handheld terminals, promptly reporting passenger flow situations, facility conditions, and other information. This instant communication mechanism greatly improves the efficiency and flexibility of platform management. For example, when a sudden large passenger flow occurs at a certain station, staff can quickly notify the control center, which can adjust the train stopping time or dispatch additional vehicles according to the actual situation, effectively relieving the congestion pressure.
In addition, the system also supports the Cross-station Collaboration function. Different stations can have real-time conversations through the system to coordinate passenger guidance and transfer arrangements. This function is particularly important during peak hours, helping to balance the passenger flow pressure of each station and optimize the overall operational efficiency. For example, if a large number of passengers are stranded at a major station where Line 1 and Line 2 intersect, through the system, the staff of the two lines can quickly negotiate and take measures such as temporarily extending the stopping time or increasing the number of trips, effectively dispersing the passenger flow and avoiding safety hazards.
Through these daily application scenarios, we can see how the subway broadcast intercom system improves operational efficiency and service quality in details. It not only simplifies the operation process of staff but also provides more accurate and timely information services for passengers, thereby comprehensively enhancing the overall level of subway operations.

Emergency Situation Handling

During the operation of the subway, a rapid response to emergency situations is of crucial importance. The subway broadcast intercom system plays an irreplaceable role at such critical moments and has become an important tool for ensuring the safety of passengers and maintaining the order of operations.
The applications of the system in emergency situations are mainly reflected in the following aspects:

1. One-touch Emergency Call: The system is equipped with a dedicated emergency button. Staff can quickly press it upon discovering a dangerous situation to immediately establish a communication link with the control center. This design significantly shortens the time for information transmission, winning precious time for subsequent rescue operations.
2. Full-duplex Two-way Intercom: The system supports real-time two-way voice communication, enabling the on-site situation to be promptly and accurately conveyed to the control center. This function is particularly crucial in emergency situations such as fires, as it can help commanders quickly assess the situation and formulate appropriate response strategies.
3. Hierarchical Control Mechanism: The system has a flexible permission management function that can automatically adjust the communication priority according to the degree of emergency. In the event of a major accident, high-level users can interrupt ongoing ordinary calls to ensure that critical information can be conveyed to the relevant personnel immediately.
4. Automatic Recording Function: The system will automatically record all emergency call contents. These records can not only be used for post-event investigation and analysis but also serve as an important reference for real-time decision-making. Especially in complex emergency situations, the recorded data can often provide crucial clues to help commanders make more accurate judgments.
5. Remote Monitoring and Intervention: The system allows the control center to remotely control the broadcast equipment on stations and trains, enabling operations such as forced broadcasting or channel switching. This function is extremely useful when evacuating passengers or issuing emergency instructions, ensuring that critical information can be quickly and widely conveyed to all relevant personnel.

Through the comprehensive application of these functions, the subway broadcast intercom system can fully exert its role in emergency situations, providing strong support for ensuring the safety of passengers and maintaining the order of operations. Whether it is a fire, a terrorist attack, or a natural disaster, the system can respond quickly to ensure the timely transmission and effective handling of critical information.

Passenger Service

The subway broadcast intercom system not only functions in emergency situations but also provides various practical services for passengers during daily operations, significantly enhancing the riding experience. The system integrates the Lost and Found function. Through an advanced lost property management system, passengers can inquire about lost items at any station, greatly increasing the retrieval rate. According to statistics, in 2018 alone, the system helped passengers retrieve more than 6,000 lost items, demonstrating its high efficiency and practicality.
In addition, the system supports Real-time Information Broadcasting, such as train schedule adjustments and transfer instructions, providing passengers with timely and accurate information services, effectively reducing the inconvenience caused by information asymmetry. These considerate services not only showcase the humanization of subway operations but also tangibly enhance the passengers' travel experience.

System Advantages

Safety Enhancement

The subway broadcast intercom system plays a key role in enhancing the safety of subway operations. As a highly integrated communication solution, the system significantly strengthens the safety guarantee capabilities of subway operations through various means such as real-time monitoring, rapid response, and intelligent analysis.
The enhancement of the system's safety is mainly reflected in the following aspects:

1. Real-time Monitoring: It is one of the core functions of the system. Through advanced video monitoring technology, the system can monitor various situations inside and outside subway stations around the clock and in all directions. This continuous monitoring can not only detect potential safety hazards in a timely manner but also provide first-hand information for the rapid response to emergencies. For example, when the system detects suspicious behavior or abnormal situations, it will immediately trigger an alarm, enabling staff to quickly intervene and take corresponding measures.
2. Rapid Response: The system also performs excellently in this regard. It adopts the One-touch Emergency Call design. Staff can quickly establish a communication link with the control center when encountering a dangerous situation. This design significantly shortens the time for information transmission, winning precious time for subsequent rescue operations. More importantly, the system supports the Full-duplex Two-way Intercom function, enabling the on-site situation to be conveyed to the control center in real time and accurately. This real-time two-way communication mechanism greatly improves the efficiency and accuracy of emergency response.
3. The system also integrates the Intelligent Analysis function, which is capable of conducting in-depth mining and real-time processing of the collected data. By analyzing data such as passenger flow volume and behavior patterns, the system can predict possible safety risks and take preventive measures in advance. This forward-looking risk management approach can not only effectively reduce the probability of accidents but also provide a more scientific and reasonable safety management plan for subway operations.
4. Remote Monitoring and Intervention: The system supports the function of remote monitoring and intervention. The control center can remotely control the broadcast equipment on stations and trains, enabling operations such as forced broadcasting or channel switching. This function is extremely useful when evacuating passengers or issuing emergency instructions, ensuring that critical information can be quickly and widely conveyed to all relevant personnel. This all-round communication guarantee mechanism greatly enhances the safety of subway operations, providing a solid guarantee for the life and property safety of passengers.

Operation Efficiency Optimization

The subway broadcast intercom system provides powerful decision-making support for subway operations through its real-time monitoring and data analysis functions. The system can collect and analyze various types of operation data in real time, such as passenger flow volume, train running status, and equipment usage status. After being processed, these data are presented to managers in the form of intuitive charts, enabling them to quickly grasp the overall operation situation and make more precise scheduling decisions.
Specifically, the advantages of the system are mainly reflected in the following aspects:

1. Automated Scheduling Optimization: The system can automatically generate the optimal train operation plan based on real-time passenger flow data and historical operation records. For example, the system may suggest increasing the number of trips during peak hours or appropriately adjusting the departure interval in sections with less passenger flow. This data-based scheduling method not only improves operation efficiency but also helps save energy and human resources.
2. Intelligent Personnel Management: The system supports the real-time location tracking and task assignment functions. Through the integrated employee positioning system, managers can keep track of the location and work status of personnel in each position at any time. This makes human resource allocation more flexible and efficient. For example, when an unexpected situation occurs at a certain station, the system can quickly locate nearby staff and automatically send task instructions, significantly shortening the response time.
3. Preventive Maintenance: The system can issue early warnings of potential fault risks through continuous monitoring and analysis of equipment operation data. This preventive maintenance strategy not only reduces the occurrence of unexpected outages but also extends the service life of equipment, significantly reducing operation costs in the long run.
4. Cross-departmental Collaboration: The system supports the multi-party real-time communication and information sharing functions. This enables different departments to quickly exchange information and coordinate actions. For example, during large events, the operation, security, and customer service departments can share passenger flow situations, safety measures, and passenger service requirements through the system in real time, jointly formulating the best response plan to ensure smooth operation during the event.

Through the comprehensive application of these functions, the subway broadcast intercom system not only improves the operational efficiency but also promotes the refined management and intelligent transformation of subway companies. It has brought higher economic benefits and social values to subway operations, truly becoming the "intelligent brain" of subway operations.
Passenger Experience Improvement
The subway broadcast intercom system significantly enhances the passenger experience in various ways. The system integrates the Lost and Found function, greatly increasing the probability of retrieving lost items. In 2018 alone, the system helped passengers retrieve more than 6,000 lost items, demonstrating its high efficiency and practicality.
In addition, the system supports Real-time Information Broadcasting, providing passengers with timely and accurate information about train schedule adjustments and transfer instructions, effectively reducing the inconvenience caused by information asymmetry. These considerate services not only showcase the humanization of subway operations but also tangibly enhance the passengers' travel experience.