Rail transit vehicle-mounted punch card machine

Abstract

The utility model discloses a rail transit vehicle -mounted punch card machine, including shell, power interface, ethernet interface, debugging interface, punch card machine mainboard, card swiping module, card swiping module wire harness, double -faced foam rubber, card swiping panel, hexagonal stud, countersunk screw etc.

Description

Technical Field

[0001] This utility model belongs to the field of rail transit technology and relates to a rail transit vehicle-mounted card reader. Background Technology

[0002] The Rail Transit TCMS (Train Control and Management System) is the "intelligent hub and neural network" of the entire train. Through a real-time data communication network that runs through the entire train, it deeply integrates the independent subsystems (such as traction, braking, air conditioning, doors, passenger information, etc.) into an organic whole, realizing centralized monitoring, intelligent diagnosis, fault early warning and data management of the entire train status. This significantly improves the automation level, operational safety and maintenance efficiency of the train, and is the core embodiment of the intelligence and integration of modern rail transit trains.

[0003] The electromagnetic environment of rail transit trains is extremely complex and harsh. It is a high-intensity, wide-band dynamic interference field composed of traction system, auxiliary power supply, control equipment and external environment. It is filled with pulse interference generated by the operation of frequency converters and circuit breakers, as well as radiation interference from on-board wireless equipment. It is characterized by dense interference sources, high intensity and wide frequency coverage, and changes in real time with the train's operating status (such as acceleration and braking). This places extremely stringent requirements on the anti-interference ability and electromagnetic compatibility of all on-board electronic equipment.

[0004] Currently, existing time clocks transmit data based on TCP or HTTP protocols, making them incompatible with train TCMS systems and preventing real-time monitoring of the clock's status. Furthermore, existing time clocks were not designed for continuous operation in complex electromagnetic environments, posing a significant challenge given the harsh electromagnetic conditions of trains. They also cannot maintain stable operation in the face of mechanical vibrations and the train's operating environment. The existing time clocks use button batteries as backup power, requiring periodic battery replacements and compromising long-term clock operation. Finally, existing time clocks cannot restart their internal load circuitry, necessitating manual power-off restarts in extreme situations to restore normal operation. Summary of the Invention

[0005] Purpose of the utility model: The purpose of this utility model is to provide a rail transit vehicle-mounted time clock that adopts a multi-level electromagnetic compatibility protection design, can work continuously in complex electromagnetic environments, provides effective protection for internal components, and can maintain the clock's long-term operation.

[0006] Technical solution: The present invention provides a rail transit vehicle-mounted card reader, comprising an integrally formed shell, with openings on the connector mounting panel and the top of the shell, and the other surfaces being closed. The openings on the connector mounting panel include power connector mounting holes, debugging interface mounting holes, and Ethernet connector mounting holes. Power connectors, Type-C connectors, and Ethernet connectors are respectively installed in the power connector mounting holes, debugging interface mounting holes, and Ethernet connector mounting holes. The power connectors and Ethernet connectors are fastened by nuts after passing through the power connector mounting holes and Ethernet connector mounting holes, and the Type-C connector is fastened by a matching Type-C connector waterproof rubber ring after passing through the debugging interface mounting hole.

[0007] Furthermore, a motherboard mounting step is installed on the bottom side inside the housing, and the motherboard is installed on the motherboard mounting step. The motherboard is secured to the motherboard by four M3×35mm hexagonal copper studs. The card reader module is then locked to the four M3×35mm hexagonal copper studs by four M3mm countersunk screws passing through the four corners of the card reader module.

[0008] Furthermore, the motherboard includes an interconnected USB-to-UART circuit, a power supply circuit, and a CPU; The USB to UART circuit is electrically connected to the Type-C connector and the CPU. The power supply circuit is electrically connected to the power connector and adopts a three-level transient protection design. The first-level transient protection circuit consists of high-flow devices to provide a high-flow discharge path for transient interference. The second-level transient protection circuit consists of decoupling components to prevent transient interference from entering the subsequent circuit. The third-level transient protection circuit consists of low-voltage protection components to provide a discharge path for transient residual voltage, thereby protecting the subsequent circuit. The power supply circuit load power is controlled by the processor. The power supply is directly supplied to the processor after being regulated. After the processor starts working, it controls the first switch and the second switch to close to supply power to the load circuit. The load circuit includes interconnected Ethernet circuits, RTC clock circuits, RTC clock backup power supplies, RAM, ROM, and all circuits of the card reader module. The Ethernet circuit is electrically connected to the Ethernet connector and the CPU. It adopts a two-stage transient protection design. The first stage transient protection circuit is composed of high-flow components to provide a high-flow discharge path for transient interference. The second stage transient protection circuit is composed of low-voltage protection components to provide a discharge path for transient residual voltage, thereby protecting the subsequent circuits. The RTC clock circuit is electrically connected to the RTC clock backup power supply and the CPU; The RTC clock backup power supply includes a current limiting element, a charging switch, a discharging switch, and a rechargeable backup power supply. Both the RAM and ROM are electrically connected to the CPU.

[0009] Furthermore, the card reader module includes interconnected MCU circuit, MCU reset monitoring circuit, human-machine interaction circuit, and RFID radio frequency circuit; The MCU circuit is electrically connected to the CPU, which adopts a Cortex-M3 architecture processor. The MCU reset monitoring circuit is electrically connected to the MCU circuit and adopts a hardware watchdog design. The human-computer interaction circuit includes a buzzer circuit, a card swiping indicator circuit, an RFID radio frequency circuit, and a working indicator circuit that are electrically connected to the MCU circuit, and is used for card-swiping human-computer interaction; The RFID radio frequency circuit includes an RFID radio frequency chip, a radio frequency transmitting circuit, a filtering circuit, an impedance matching circuit, and a radio frequency antenna, and is used for RFID card identification.

[0010] Furthermore, a double-sided foam adhesive bonding step is installed in the hollowed-out area at the top of the outer shell, and double-sided foam adhesive is applied to the double-sided foam adhesive bonding step. A card reader panel with a size that matches the size of the double-sided foam adhesive bonding step is also installed on the upper side of the housing; a working indicator light display window, a card reader indicator light display window, and a card reader mark are provided on the surface of the card reader panel.

[0011] Furthermore, the thickness of the card reader panel is greater than the thickness of the double-sided foam adhesive step.

[0012] Furthermore, both the power connector and the Ethernet connector adopt a panel-mount socket design, which can solder cables and use wire harnesses to connect to the motherboard's power interface and Ethernet interface respectively. The sockets of the power connector and the Ethernet connector both have an IP67 protection rating. During installation, the power connector socket harness and the Ethernet connector socket harness are both fitted with waterproof rubber rings on the outside of the housing, and the inside of the housing is secured with nuts to ensure that the card reader's protection level reaches IP65.

[0013] Furthermore, two mounting brackets, mounting bracket one and mounting bracket two, are respectively installed on both sides of the outer shell. The two mounting brackets secure the card reader to the train with four bolts.

[0014] Beneficial effects: Compared with the prior art, this utility model has the following significant advantages: 1. The device can be integrated into the train TCMS system, and the train can monitor the status of the card reader in real time; 2. The device has an electromagnetic compatibility design, which can work stably in the complex electromagnetic environment of the rail train; 3. The device has an IP65 protection rating, which can effectively protect the internal components; 4. The mounting bracket in the device can firmly fix the card reader to the train, preventing it from being affected by mechanical vibration; 5. The backup power supply of the RTC clock of the device adopts a rechargeable design, which can keep the clock working continuously; 6. The load power supply of the device is controlled by the processor, and the whole machine can be remotely restarted by restarting the operating system. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is an exploded view of the structure of this utility model; Figure 3 This is a schematic diagram of the outer shell structure in this utility model; Figure 4 This is a schematic diagram of the card reader panel in this utility model; Figure 5 This is a hardware architecture diagram of this utility model; Figure 6 This is a schematic diagram of the power supply protection circuit in this utility model; Figure 7 This is the schematic diagram of the power control circuit in this utility model; Figure 8 This is the schematic diagram of the RTC clock circuit in this utility model; Figure 9 This is the schematic diagram of the Ethernet circuit in this utility model; In the diagram, 100 is the card reader panel, 101 is the work indicator light display window, 102 is the card reader indicator light display window, and 103 is the card reader icon. 200 is the outer casing, 201 is mounting bracket one, 202 is mounting bracket two, 203 is the power connector mounting hole, 204 is the debugging interface mounting hole, 205 is the Ethernet connector mounting hole, 206 is the motherboard mounting step, and 207 is the double-sided foam adhesive bonding step. 300 is the power connector; 400 is a Type-C connector, and 401 is a waterproof rubber ring for a Type-C connector; 500 is an Ethernet connector; 600 is the card reader module, 601 is the MCU circuit, 602 is the buzzer circuit, 603 is the card swipe indicator circuit, 604 is the RFID radio frequency circuit, 605 is the radio frequency antenna circuit, 606 is the working indicator circuit, and 607 is the MCU reset monitoring circuit. 700 is the motherboard, 701 is the Ethernet circuit, 702 is the USB to UART circuit, 703 is the power supply circuit, 704 is the RTC clock circuit, 705 is the RTC clock backup power supply, 706 is RAM, 707 is ROM, and 708 is the CPU. 801 is an M3mm countersunk screw, 802 is double-sided foam adhesive, and 803 is an M3×35mm hexagonal brass stud. Detailed Implementation

[0016] The specific technical solution of this utility model will be further described in detail below with reference to specific examples.

[0017] like Figure 1-5 As shown, the rail transit vehicle-mounted card reader of this utility model includes a card reader panel 100, a housing 200, a power connector 300, a type-C connector 400, an Ethernet connector 500, a card reader module 600, a motherboard 700, an Ethernet interface, a debugging interface, M3×35mm hexagonal copper studs 803, M3mm countersunk screws 801, double-sided foam adhesive 802, a card reader indicator light circuit 603, a working indicator light circuit 606, a mounting bracket one 201, a mounting bracket two 202, etc.

[0018] The outer casing 100 adopts a one-piece molding design, with openings only on the connector mounting panel and the top, while the other surfaces are closed. With only the connector mounting panel and top opening, the interior of the outer casing 100 is almost completely sealed after the connector and card reader panel 100 are installed. The card reader has an overall protection rating of IP65, effectively protecting its internal components. The card reader uses an aluminum alloy casing and transient protection design, effectively resisting electromagnetic interference from the train. The mounting brackets on both sides of the aluminum alloy casing 100 are secured with two M6 bolts each, ensuring that the card reader is not affected by train mechanical vibrations.

[0019] The connector mounting panel has a power connector mounting hole 203, a debugging interface mounting hole 204, and an Ethernet connector mounting hole 205. The power connector 300 and the Ethernet connector pass through the mounting holes (power connector mounting hole 203 and Ethernet connector mounting hole 205) on the side of the housing 200 and are fastened inside the housing 200 with nuts (flange nuts). The type-c connector 400 passes through the mounting hole (debugging interface mounting hole 204) on the side of the housing 200 and is fastened inside the housing 200 with a type-c connector waterproof rubber ring 401. After installing the type-c connector waterproof rubber ring 401 on the type-c connector 400 on the motherboard 700, align the motherboard connector interface with the housing connector mounting panel, place the motherboard 700 on the mounting step inside the housing 200, and then use four M3×35mm hexagonal copper studs 803 to fix the motherboard 700. Finally, electrically connect the socket harness of the power connector 300 and the socket harness of the Ethernet connector 600 to the power interface and Ethernet interface of the motherboard 700, respectively.

[0020] Inside the housing 200, at the four corners of the bottom, there are motherboard mounting steps 206 for mounting the motherboard 700. The motherboard 700 is fastened with four hexagonal studs (M3×35mm hexagonal copper studs 803), and the card reader module 600 is locked onto the four M3×35mm hexagonal copper studs 803 with four countersunk screws (M3mm countersunk screws 801). A double-sided foam adhesive bonding step 207 is also installed at the top cutout of the housing 200, and double-sided foam adhesive 802 is applied to the double-sided foam adhesive bonding step 207. After the card reader module 600 is electrically connected to the motherboard 700 using a wire harness, it is then fixed to the M3×35mm hexagonal copper stud 803 using a 3mm countersunk screw 801. After the card reader panel 100 is glued with double-sided foam adhesive 802 on all four sides, it is installed at the mounting step of the housing 200. Finally, a pressing device is used to evenly press the card reader panel 100 and the housing 200 together to ensure a firm bond.

[0021] The size of the card reader panel 100 is consistent with the size of the double-sided foam adhesive step 207 on the outer shell 200, and the card reader panel 100 is tightly bonded along the mounting step on the outer shell 200.

[0022] The thickness of the card reader panel 100 is greater than the bonding step (double-sided foam adhesive bonding step 207) of the outer shell 200, so that the card reader panel 100 can be kept horizontal with the outer mounting panel when installed. The card reader panel 100 is made of non-metallic material that meets the EN45545-HL3 fire-retardant standard. Its surface is provided with a work indicator light display window 101, a card reader indicator light display window 102, and a card reader logo 103 for human-computer interaction and to display the card-swiping status. The bottom surface of the card reader panel 100 needs to be painted. The first step is to paint the card reader logo, and the second step is to paint the base color of the card reader panel. When painting the base color ink, the work indicator light display window 101 and the card reader indicator light display window 102 must be avoided. The card reader logo 103 and the indicator light display window are used for human-computer interaction display.

[0023] Mounting brackets (mounting bracket 1 201 and mounting bracket 2 202) are installed on both sides of the outer casing 200. The card reader is fastened to the train with four bolts to prevent the mechanical vibration of the train from affecting the card reader.

[0024] The motherboard 700 includes a power supply circuit 703, a USB to UART circuit 702, an Ethernet circuit 701, an RTC clock circuit 704, an RTC clock backup power supply 705, a CPU 708, a ROM 707, a RAM 706, a processor circuit, a debugging circuit, etc.

[0025] The power supply circuit 703 employs a three-stage transient protection design. The first-stage transient protection circuit consists of high-current devices, providing a high-current discharge path for transient interference. The second-stage transient protection circuit consists of decoupling components to prevent transient interference from entering subsequent circuits. The third-stage transient protection circuit consists of low-voltage protection components, providing a discharge path for transient residual voltage, thereby protecting subsequent circuits. This three-stage protection scheme of the power supply circuit can withstand and prevent four-stage transient interference.

[0026] The power supply circuit 703 load power is controlled by the processor. The power supply is directly supplied to the processor after being regulated. After the processor starts working, it controls the first switch and the second switch to close to supply power to the load circuit. The load circuit includes the RTC clock circuit 704, the RTC clock backup power supply 705, the Ethernet circuit 701, and all circuits of the card reader module 600. A power-level restart of the entire machine can be achieved by controlling the processor (operating system) to restart.

[0027] The Ethernet circuit 701 employs a two-stage transient protection design. The first-stage transient protection circuit consists of high-flow components, providing a high-flow discharge path for transient interference. The second-stage transient protection circuit consists of low-voltage protection components, providing a discharge path for transient residual voltage, thereby protecting downstream circuits. The Ethernet transient protection circuit can prevent four levels of transient interference.

[0028] The RTC backup power circuit 705 includes a current limiting element, a charging switch, a discharging switch, and a rechargeable backup power supply. It employs a rechargeable supercapacitor design to ensure continuous clock operation. Specifically, when the backup power supply is low, the charging switch closes, the discharging switch opens, and the backup power supply begins charging. The current limiting element controls the charging current to prevent excessive charging current and damage to the backup power supply. When the backup power supply is fully charged, both the charging and discharging switches open, stopping the backup power supply from overcharging and causing damage. When the time clock is powered off, the discharging switch closes, providing operating voltage to the clock circuit to ensure continuous clock operation.

[0029] The CPU708 uses NXP's i.mx6ull processor, paired with 512MB of memory and an 8GB hard drive, and is capable of running the Linux operating system.

[0030] The processor circuit includes a Cortex-A7 architecture processor, a large-capacity storage chip, and a large-capacity memory chip; the processor circuit can run the Linux operating system and the time clock application software developed based on the Linux platform; the time clock application software is developed based on the TRDP transmission protocol, and the data of the time clock application software can be connected to the train TCMS system, which can monitor the status of the time clock in real time.

[0031] The card reader module 600 includes an MCU circuit 601, an MCU reset monitoring circuit 607, a human-machine interaction circuit, an RFID radio frequency circuit 604, etc. The MCU circuit 601 is designed using ST's STM32F103CBT6 processor; The MCU reset monitoring circuit 607 adopts a hardware watchdog design to ensure the stable operation of the card reading program; The human-computer interaction circuit includes a working indicator light circuit 606, a card swiping indicator light circuit 603, and a buzzer circuit 602, which are used for card-swiping human-computer interaction. The buzzer circuit 602 adopts a high-decibel buzzer design to indicate to the user whether the check-in was successful; The card reader indicator circuit 603 adopts an RGB LED design, displaying "green" when the card is successfully swiped and "red" when the card fails to swipe. The working indicator circuit 606 also adopts an RGB LED design, and the "blue" indicator light flashes periodically when the card reader program is running; The RFID radio frequency circuit 604 includes an RFID radio frequency chip, a radio frequency transmitting circuit, a filtering circuit, an impedance matching circuit, and an antenna circuit, and is used for RFID card identification.

[0032] Both the power connector 300 and the Ethernet connector 500 adopt a panel-mount socket design, which can be used to solder cables and can be connected to the power interface and Ethernet interface of the motherboard 700 respectively using wire harnesses. The power connector 300 uses an M12S coded connector, which has an IP67 protection rating and allows for cable soldering at its tail.

[0033] The Ethernet connector 500 uses the M12D coded connector, which also has an IP67 protection rating and can be soldered to wire harnesses at its tail.

[0034] The sockets of the power connector 300 and the Ethernet connector 500 both have an IP67 protection rating. When installing the socket harness of the power connector 300 and the socket harness of the Ethernet connector 500, waterproof rubber rings are installed on the outside of the housing 200, and nuts are used to tighten them inside the housing 200 to ensure that the protection level of the time clock reaches IP65.

[0035] The power protection circuit in this device is as follows: Figure 6 As shown, the circuit includes a varistor RV15, a gas discharge tube G1, resettable fuses F1 and F2, a TVS diode Z1, and a diode D1. The first-stage transient protection circuit consists of the varistor RV15 and the gas discharge tube G1. The two ends of RV15 are electrically connected to the positive and negative terminals of the power supply, respectively. One end of G1 is electrically connected to the negative terminal of the power supply, and the other end is electrically connected to the protective grounding metal pad of the motherboard 700. The protective grounding metal pad of the motherboard 700 is mechanically connected to the metal casing 200 via an M3×35mm hexagonal copper stud 803. The protective grounding pin in the power connector 300 is also electrically connected to the protective grounding metal pad of the motherboard 700. The first stage provides a high-flow, low-impedance discharge path for the equipment, thus protecting it from transient damage. The second stage transient protection circuit consists of resettable fuses F1 and F2, which are connected in series to the back end of the varistor. The series connection of F1 and F2 increases the impedance and reduces the transient residual voltage that may enter the subsequent circuit. The third stage transient protection circuit consists of a TVS diode Z1, with one end of Z1 electrically connected to F2 and the other end electrically connected to the negative terminal of the power supply. After the first two stages of transient protection, the final transient residual voltage is absorbed by Z1, further protecting the subsequent circuit. It has been verified that the transient protection circuit composed of three stages can prevent four levels of transient interference.

[0036] The power control circuit in this device is as follows: Figure 7As shown, the power network VSYS_3V3 directly provides the operating voltage to the CPU708 via the output of the voltage regulator chip. The +3.3V power network is controlled by PMOS transistor Q9 and NMOS transistor Q10. When the CPU708 is working, the control signal PMIC-ON_REQ outputs a high level, which causes the gate of NMOS transistor Q10 to be high, and the source and drain of Q10 to begin conducting. After Q10 is turned on, the gate of PMOS transistor Q9 is low, and the drain and source of Q9 begin conducting, connecting the VSYS_3V3 network and the +3.3V network to provide the operating voltage to the load. By directly controlling the CPU708, the conduction of Q9 and Q10 can be indirectly controlled, thus achieving the purpose of controlling the device to restart.

[0037] The clock circuit in this device is as follows: Figure 8 As shown, the circuit consists of a backup power supply circuit and a clock circuit. The backup power supply uses a supercapacitor BT1. When the device is powered on, on the one hand, when the voltage at the first pin of diode D2 is +3.3V and the voltage at the third pin is lower than +3V, the first diode of diode D2 starts to conduct, charging the supercapacitor BT1. When the supercapacitor BT1 is fully charged, when the voltage at the third pin of D2 is greater than or equal to +3V, the first diode of D2 starts to cut off, and the supercapacitor BT1 stops charging. On the other hand, the first diode of diode D13 conducts, providing the operating voltage for the clock circuit, and the second diode of diode D13 is cut off, so the BT1 diode stops discharging and only charges. Resistor R25 is a charging current-limiting resistor to prevent excessive charging current from damaging the supercapacitor BT1. When the device is powered off, the second diode of diode D13 starts to conduct, providing the operating voltage for the clock circuit, ensuring the clock continues to operate.

[0038] The Ethernet circuit 701 in this device is as follows: Figure 9As shown, the circuit includes a PHY chip circuit, a network transformer circuit, and a transient protection circuit. The PHY chip U13 uses the YT8512H chip from Yutai Microelectronics. The PHY chip is electrically connected to the CPU via an RMII communication interface. The network transformer circuit consists of capacitors C62 and C63, a network transformer L1, resistors R1 and R2, and capacitor C3. One side of the network transformer is electrically connected to the PHY chip using two pairs of differential signals, and the other side is also electrically connected to connector P2 using two pairs of differential signals. The first-stage transient protection circuit... Composed of gas discharge tubes GD2 and GD3, one end of the gas discharge tube is electrically connected to the center tap of the network transformer, and the other end is electrically connected to the motherboard protective ground, providing high-volume transient protection for the Ethernet circuit 701; the second-stage transient protection circuit consists of TVS diodes E1 and E2, which are connected between two pairs of differential signals between the PHY chip and the network transformer, respectively, to absorb the remaining transient residual voltage for the Ethernet circuit 701; it has been verified that this two-stage transient protection circuit for Ethernet can prevent four levels of transient interference.

Claims

1. A vehicle-mounted card reader for rail transit, characterized in that, It includes an integrally molded housing (200), with openings on the connector mounting panel and top of the housing (200), and the other surfaces are closed; The openings on the connector mounting panel include a power connector mounting hole (203), a debugging interface mounting hole (204), and an Ethernet connector mounting hole (205). A power connector (300), a type-C connector (400), and an Ethernet connector (500) are respectively installed in the power connector mounting hole (203), the debugging interface mounting hole (204), and the Ethernet connector mounting hole (205). The power connector (300) and the Ethernet connector (500) are fastened by the installed nuts after passing through the power connector mounting hole (203) and the Ethernet connector mounting hole (205). The type-C connector (400) is fastened by the matching type-C connector waterproof rubber ring (401) after passing through the debugging interface mounting hole (204).

2. The rail transit vehicle-mounted card reader according to claim 1, characterized in that, A motherboard mounting step (206) is installed on the bottom side inside the housing (200), and a motherboard (700) is installed on the motherboard mounting step (206). The motherboard mounting step (206) secures the motherboard (700) with four M3×35mm hexagonal copper studs (803). The card reader module (600) is then locked onto the four M3×35mm hexagonal copper studs (803) by four M3mm countersunk screws (801) passing through the four corners of the card reader module (600).

3. The rail transit vehicle-mounted card reader according to claim 2, characterized in that, The motherboard (700) includes a USB to UART circuit (702), a power supply circuit (703), and a CPU (708) that are interconnected. The USB to UART circuit (702) is electrically connected to the type-c connector (400) and the CPU (708). The power supply circuit (703) is electrically connected to the power connector (300), and it adopts a three-level transient protection design. The first-level transient protection circuit is composed of high-flow devices, which provide a high-flow discharge path for transient interference. The second-stage transient protection circuit consists of decoupling components to prevent transient interference from entering the subsequent circuits; the third-stage transient protection circuit consists of low-voltage protection components to provide a discharge path for transient residual voltage, thereby protecting the subsequent circuits. The power supply circuit (703) load power is controlled by the processor. The power supply is directly supplied to the processor after being regulated. After the processor starts working, it controls the first switch and the second switch to close to supply power to the load circuit. The load circuit includes all the interconnected circuits of the Ethernet circuit (701), RTC clock circuit (704), RTC clock backup power supply (705), RAM (706), ROM (707) and card reader module (600); The Ethernet circuit (701) is electrically connected to the Ethernet connector (500) and the CPU (708). It adopts a two-stage transient protection design. The first stage transient protection circuit is composed of high-flow components to provide a high-flow discharge path for transient interference. The second stage transient protection circuit is composed of low-voltage protection components to provide a discharge path for transient residual voltage, thereby protecting the subsequent circuits. The RTC clock circuit (704) is electrically connected to the RTC clock backup power supply (705) and the CPU (708). The RTC clock backup power supply (705) includes a current limiting element, a charging switch, a discharging switch, and a rechargeable backup power supply. Both the RAM (706) and ROM (707) are electrically connected to the CPU (708).

4. The rail transit vehicle-mounted card reader according to claim 3, characterized in that, The card reader module (600) includes an interconnected MCU circuit (601), an MCU reset monitoring circuit (607), a human-machine interaction circuit, and an RFID radio frequency circuit (604). The MCU circuit (601) is electrically connected to the CPU (708), which adopts a Cortex-M3 architecture processor; The MCU reset monitoring circuit (607) is electrically connected to the MCU circuit (601), and it adopts a hardware watchdog design. The human-computer interaction circuit includes a buzzer circuit (602) electrically connected to the MCU circuit (601), a card swiping indicator circuit (603), an RFID radio frequency circuit (604), and a work indicator circuit (606), which are used for card-swiping human-computer interaction. The RFID radio frequency circuit (604) includes an RFID radio frequency chip, a radio frequency transmitting circuit, a filtering circuit, an impedance matching circuit, and a radio frequency antenna (605), which is used for RFID card identification.

5. The rail transit vehicle-mounted card reader according to claim 2, characterized in that, A double-sided foam adhesive bonding step (207) is installed at the hollowed-out part at the top of the outer shell (200), and double-sided foam adhesive (802) is applied to the double-sided foam adhesive bonding step (207). A card reader panel (100) with a size that matches the size of the double-sided foam adhesive step (207) is also installed on the upper side of the outer casing (200); a working indicator light display window (101), a card reader indicator light display window (102) and a card reader mark (103) are provided on the surface of the card reader panel (100).

6. The rail transit vehicle-mounted card reader according to claim 5, characterized in that, The thickness of the card reader panel (100) is greater than the thickness of the double-sided foam adhesive step (207).

7. The rail transit vehicle-mounted card reader according to claim 1, characterized in that, Both the power connector (300) and the Ethernet connector (500) adopt a panel-mount socket design, which can solder cables and use wire harnesses to connect to the power interface and Ethernet interface of the motherboard (700) respectively. The sockets of the power connector (300) and the Ethernet connector (500) both have an IP67 protection rating. During installation, the socket harness of the power connector (300) and the socket harness of the Ethernet connector (500) are both fitted with waterproof rubber rings on the outside of the housing (200), and nuts are used to lock the inside of the housing (200) to ensure that the protection level of the card reader reaches IP65.

8. The rail transit vehicle-mounted card reader according to claim 1, characterized in that, Two mounting brackets, mounting bracket one (201) and mounting bracket two (202), are installed on both sides of the outer shell (200). The two mounting brackets are used to fasten the card reader to the train with four bolts.

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