A SIM card hub device based on a one-expansion-three architecture

Abstract

This utility model discloses a SIM card hub device based on a one-to-three architecture. A connector is used to match and connect with the SIM card slot interface of a mobile terminal to establish a communication link with the mobile terminal's cellular module. The connector is connected to the power supply terminal of the control unit via a power management circuit branch. The connector is also connected to the access port of a gating switch group via a signal transmission path. The gating switch group includes at least two cascaded gating switches, and the access port of the gating switch group is connected to the signal transmission path. Each gating port of the final-stage gating switch is connected to a different SIM card interface. The control signal output terminal of the control unit is connected to the control terminal of the gating switch group. The input terminal of the power supply branch of the power management circuit is connected to the connector. By adopting the architecture of a cascaded gating switch group, this device successfully expands from a single physical SIM card slot interface of the mobile terminal to three or more SIM card interfaces.

Description

Technical Field

[0001] This utility model relates to the field of mobile communication technology, and in particular to a SIM card hub device based on a one-to-three architecture. Background Technology

[0002] In scenarios such as Industrial IoT and vehicle communication that rely on cellular networks, fluctuations in the on-site operator network often lead to communication interruptions for equipment. Existing systems generally use a "disconnection and module restart" mechanism to restore connectivity: when the network times out, the device automatically restarts the cellular module to re-register with the network. However, this mechanism has significant limitations: module restart only restores the network connection of the original SIM card. If the original operator's base station is faulty or has a weak signal, restarting still cannot solve the fundamental problem, causing the device to fall into a cycle of "disconnection-restart-disconnection again," which seriously affects service continuity.

[0003] With the development of mobile communication technology, users' demands for multi-carrier network access, international roaming, and multi-SIM card management for IoT devices are increasing. Traditional single-SIM card slot terminals require manual SIM card replacement, which is cumbersome and prone to damaging the card. Existing multi-SIM card expansion devices mostly adopt a "one-to-two" architecture and require integrated battery power, resulting in problems such as large size, high cost, and switching delays. For example, in existing technologies, external SIM card expansion devices achieve switching by integrating a microprocessor and battery, but the battery increases hardware costs and device size, and the switching process requires restarting the terminal, resulting in a poor user experience. Utility Model Content

[0004] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of this utility model is to provide a SIM card hub device based on a one-to-three architecture to solve the problems mentioned in the background art.

[0005] The technical solution adopted by this utility model to solve its technical problem is: a SIM card hub device based on a one-to-three architecture, including a connector, a control unit, a gating switch group, multiple SIM card interfaces, a signal transmission path, and a power management circuit;

[0006] The connector is used to match and connect with the SIM card slot interface of the mobile terminal to establish a communication link with the cellular module of the mobile terminal.

[0007] The connector is connected to the power supply terminal of the control unit through the power-drawing branch of the power management circuit, and is used to supply power to the control unit; the connector is also connected to the access port of the gating switch group through the signal transmission path;

[0008] The gating switch group includes two cascaded gating switches, and the access port of the gating switch group is connected to the signal transmission path; wherein, one gating port of the first-stage gating switch is directly connected to a first SIM card interface, and the other gating port is connected to the access port of the next-stage gating switch; each gating port of the final-stage gating switch is connected to a different SIM card interface.

[0009] The multiple SIM card interfaces are used to accommodate SIM cards respectively;

[0010] The control signal output terminal of the control unit is connected to the control terminal of the selection switch group, and is used to control the selection state of each selection switch, selectively connecting any of the SIM card interfaces to the signal transmission path;

[0011] The input terminal of the power supply branch of the power management circuit is connected to the connector.

[0012] As a further improvement of this utility model: the power supply branch of the power management circuit integrates a soft-start circuit, the enable terminal of the soft-start circuit is connected to the control unit, and the control unit controls the soft-start circuit to output a power supply signal to the SIM card, in which the soft-start circuit voltage gradually rises from zero to the rated operating voltage.

[0013] As a further improvement of this utility model: the soft-start circuit includes a linear regulator, the enable pin of which is connected to the GPIO pin of the control unit, and the control unit controls the output voltage of the linear regulator by outputting a pulse width modulation signal through the GPIO pin.

[0014] As a further improvement of this utility model: any one of the gating switches in the gating switch group is a single-pole double-throw analog switch, and the on-resistance of the gating switch is less than 10 ohms.

[0015] As a further improvement of this utility model: the control unit is a microcontroller based on the ARM Cortex-M0 core, and the microcontroller communicates with the control terminal of the gating switch group through the I2C bus or the SPI bus.

[0016] As a further improvement of this utility model, it also includes a memory, which is electrically connected to the control unit, and is used to store the identification information and status flags of the SIM cards connected to each SIM card interface.

[0017] As a further improvement of this utility model: at least one of the plurality of SIM card interfaces is a Nano-SIM card socket, and the Nano-SIM card socket is connected in series with an ESD protection device.

[0018] As a further improvement of this utility model: the gating switch group is composed of two cascaded single-pole double-throw switches, and the number of the multiple SIM card interfaces is three;

[0019] The moving end of the first-stage single-pole double-throw switch is connected to the signal transmission path, the first stationary end of the first-stage single-pole double-throw switch is connected to the first SIM card interface, and the second stationary end of the first-stage single-pole double-throw switch is connected to the moving end of the second-stage single-pole double-throw switch.

[0020] The first stationary terminal of the second-stage single-pole double-throw switch is connected to the second SIM card interface, and the second stationary terminal of the second-stage single-pole double-throw switch is connected to the third SIM card interface.

[0021] As a further improvement of this utility model, the device also includes a network status acquisition module and an automatic decision-making module;

[0022] The input terminal of the network status acquisition module is connected to the analog-to-digital converter pin of the control unit to acquire the electrical signal parameters of the network quality of each SIM card.

[0023] The automatic decision-making module is integrated into the control unit. The automatic decision-making module is communicatively connected to the network status acquisition module and the data storage. The automatic decision-making module outputs a switching command to the control terminal of the gating switch group.

[0024] As a further improvement of this utility model, a status indicator light is also provided, which is connected to the microprocessor.

[0025] Compared with the prior art, the beneficial effects of this utility model are:

[0026] This invention, through the collaborative design of a cascaded selection switch group and dual-channel power management, achieves seamless expansion from a single card slot to three SIM card interfaces for the first time without the need for external battery power. It provides redundancy backup capability for three networks, greatly improving the network connection reliability of the device in scenarios such as industrial IoT and cross-border roaming. Furthermore, through power management with integrated soft-start circuitry, the output voltage of the linear regulator is precisely controlled by the microcontroller's PWM signal, eliminating the risk of current surges during SIM card hot-swapping and switching, and reducing the probability of damage to the SIM card and terminal module. On the other hand, the built-in network status acquisition and automatic decision-making module monitors network quality in real time, enabling the system to automatically switch to the optimal network, avoiding service interruptions caused by dropped connections and restarts, and ensuring the continuity of voice calls and data transmission. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the SIM card hub device architecture of this utility model. Detailed Implementation

[0028] In order to clearly and completely understand the technical solution, the present invention will be further described in conjunction with the embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0030] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0031] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0032] according to Figure 1 As shown, an embodiment of this utility model provides a SIM card hub device based on a one-to-three architecture, including a connector, a control unit, a gating switch group, multiple SIM card interfaces, a signal transmission path, and a power management circuit.

[0033] The connector is used to match and connect with the SIM card slot interface of the mobile terminal to establish a communication link with the cellular module of the mobile terminal.

[0034] The connector is connected to the power supply terminal of the control unit through the power-drawing branch of the power management circuit, and is used to supply power to the control unit; the connector is also connected to the access port of the gating switch group through the signal transmission path;

[0035] The gating switch group includes two cascaded gating switches, and the access port of the gating switch group is connected to the signal transmission path; wherein, one gating port of the first-stage gating switch is directly connected to a first SIM card interface, and the other gating port is connected to the access port of the next-stage gating switch; each gating port of the final-stage gating switch is connected to a different SIM card interface.

[0036] The multiple SIM card interfaces are used to accommodate SIM cards respectively;

[0037] The control signal output terminal of the control unit is connected to the control terminal of the selection switch group, and is used to control the selection state of each selection switch, selectively connecting any one of the plurality of SIM card interfaces to the signal transmission path;

[0038] The input terminal of the power supply branch of the power management circuit is connected to the connector.

[0039] The SIM card hub device based on a one-to-three architecture according to this application mainly includes a connector, a control unit, a selection switch group, multiple SIM card interfaces, a signal transmission path, and a power management circuit. By adopting a cascaded selection switch group architecture, the device successfully expands from a single physical SIM card slot interface of the mobile terminal to three or more SIM card interfaces. One port of the first-level selection switch is directly connected to a card slot, and the other port is cascaded to the next-level switch. The multiple ports of the final-level switch are then connected to different card slots, realizing a one-to-three SIM card slot expansion. A dual-path power management circuit is also adopted. The power supply branch draws power directly from the mobile terminal through the connector to power the control unit, ensuring the operation of the control core. The power supply branch also draws power from the terminal and powers the selected SIM card, eliminating the need for an additional battery or external power supply, greatly reducing the device size and lowering hardware costs. In this embodiment, the control unit uniformly controls the state of all selection switches, realizing the selection control of multiple SIM card interfaces. Users can choose which SIM card interface to connect to the signal transmission path for communication with the mobile terminal as needed. The switching process is completed by an electronic switch, avoiding the inconvenience and risk of damage caused by physically inserting and removing SIM cards.

[0040] In one embodiment of this utility model, a soft-start circuit is integrated into the power supply branch of the power management circuit. The enable terminal of the soft-start circuit is connected to the control unit. The control unit controls the soft-start circuit to output a power supply signal to the SIM card, in which the soft-start circuit voltage gradually increases from zero to the rated operating voltage.

[0041] A SIM card is a precision chip highly sensitive to voltage and current. In traditional handover schemes, the SIM card's power-on is instantaneous, generating a significant transient inrush current. Furthermore, after power-on, the SIM card needs to complete a reset and initialization communication process. If the power supply voltage is established instantaneously, it may cause power fluctuations and signal instability, leading to initialization failure and rendering the SIM card unrecognizable. This embodiment utilizes a soft-start circuit to smoothly and linearly increase the output voltage from zero volts to the rated operating voltage, rather than abruptly jumping. This effectively suppresses inrush current and significantly reduces the risk of physical damage to the SIM card's internal circuitry or the terminal's cellular module I / O ports caused by current stress.

[0042] In one embodiment of this invention, the soft-start circuit includes a linear regulator. The enable pin of the linear regulator is connected to the GPIO pin of the control unit. The control unit outputs a pulse width modulation (PWM) signal through the GPIO pin to control the output voltage of the linear regulator. This embodiment utilizes the existing general-purpose input / output pins of the control unit and its built-in PWM generator, controlling the frequency and duty cycle of the PWM signal through software programming using existing technology. The PWM signal acts on the enable pin of the linear regulator, indirectly modulating the rising slope of its output voltage by controlling the ratio of its switching time.

[0043] In one embodiment of this utility model, any one of the gating switches in the gating switch group is a single-pole double-throw analog switch, and the on-resistance of the gating switch is less than 10 ohms.

[0044] The on-resistance of the selector switch forms a series voltage divider with the input / output impedance of the SIM card and the terminal baseband chip. The low on-resistance of less than 10 ohms ensures that the voltage amplitude attenuation of multiple key high-frequency signals such as clock, data, and reset of the SIM card interface is controlled at an extremely low level when passing through the switch, effectively avoiding problems such as read / write errors, initialization failures, or communication interruptions that may be caused by signal amplitude reduction.

[0045] In one embodiment of this invention, the control unit is a microcontroller based on an ARM Cortex-M0 core. The microcontroller communicates with the control terminal of the gating switch group via an I2C bus or an SPI bus. The ARM Cortex-M0 core microcontroller boasts significantly higher computing performance and processing efficiency than traditional 8-bit MCUs, easily running complex switching logic, communication protocols, and even simple intelligent algorithms. Simultaneously, the Cortex-M0 core is renowned for its extremely low power consumption and excellent cost control, perfectly meeting the stringent requirements of this device—no external power supply and cost control—providing the optimal performance-to-power ratio for achieving core control functions. Using standard synchronous serial buses like I2C or SPI to communicate with the gating switches simplifies PCB layout and routing. Bus communication offers high reliability and anti-interference capabilities. Instructions are transmitted in data packets, and the built-in clock synchronization and acknowledgment mechanisms ensure accurate delivery and execution of control commands, avoiding switching state errors caused by signal asynchrony. On the other hand, the I2C / SPI bus standard supports device addressing and multiple device mounting. If it is necessary to further expand support for more SIM card slots, it is only necessary to add corresponding gating switch chips and assign them different addresses, without changing the basic hardware architecture of the control unit.

[0046] In one embodiment of this invention, a memory is further included. The memory is electrically connected to the control unit and is used to store the identification information and status flags of the SIM cards connected to each SIM card interface. During power-on initialization, the control unit can automatically read the unique identification information of the SIM cards in each slot and persistently store it in the memory. This gives the device a memory function, enabling it to accurately identify which specific SIM card is inserted in each slot. Users can pre-set strategies, such as always using a card from operator A for data traffic transmission, and the device can automatically identify and switch to the target SIM card without requiring manual specification each time. The status flags can be used to record the current network status, whether it is enabled, and the switching history of each SIM card. Before making a switching decision, the control unit can first query the status information in the memory to quickly eliminate SIM cards marked as "invalid," "no network," or "disabled," and directly select a known available backup card. This avoids futile switching attempts to unserviceable SIM cards and lengthy network registration waiting processes, minimizing fault handover time and greatly improving system response speed.

[0047] In one embodiment of this invention, at least one of the plurality of SIM card interfaces is a Nano-SIM card holder, and the Nano-SIM card holder is connected in series with an ESD protection device. The SIM card interface, as a part that frequently comes into contact with external cards and undergoes hot-swapping operations, is a high-risk channel for electrostatic discharge (ESD). High-voltage ESD pulses generated by the human body or the environment can easily penetrate the device through the card holder contacts, damaging the terminal's main processor baseband chip or control unit and causing permanent damage. The series-connected ESD protection device can act rapidly within nanoseconds of the occurrence of such transient high-voltage pulses, clamping them to a safe low voltage level and discharging excess current to ground. Furthermore, current mainstream smartphones, tablets, and most IoT modules use the Nano-SIM standard. Using a Nano-SIM card holder ensures that the user's SIM card can be directly inserted into this expansion device without any adapter, avoiding problems such as poor contact, signal attenuation, or card damage that may occur due to the use of adapter cards.

[0048] In one embodiment of this utility model, the gating switch group consists of two cascaded single-pole double-throw switches, and the number of the plurality of SIM card interfaces is three;

[0049] The moving end of the first-stage single-pole double-throw switch is connected to the signal transmission path, the first stationary end of the first-stage single-pole double-throw switch is connected to the first SIM card interface, and the second stationary end of the first-stage single-pole double-throw switch is connected to the moving end of the second-stage single-pole double-throw switch.

[0050] The first stationary terminal of the second-stage single-pole double-throw switch is connected to the second SIM card interface, and the second stationary terminal of the second-stage single-pole double-throw switch is connected to the third SIM card interface.

[0051] In this embodiment, the selection switch group consists of two cascaded single-pole double-throw (SPDT) switches. One channel of the first-stage SPDT switch is directly connected to the first SIM card, while the other channel is reserved as an extension channel for the second-stage SPDT switch. The two channels of the second-stage SPDT switch are connected to the second and third SIM cards, respectively. This architecture uses only two low-cost, universal second-stage SPDT switch chips to achieve selection control of three independent SIM card channels. Furthermore, this connection method defines a unique and definite signal path from each SIM card to the terminal. For example, when selecting card 1, the path is: terminal → moving end of the first-stage switch → first stationary end of the first-stage switch → card 1; when selecting card 3, the path is: terminal → moving end of the first-stage switch → second stationary end of the first-stage switch → (entering the second stage) moving end of the second-stage switch → second stationary end of the second-stage switch → card 3. This minimizes signal reflection and attenuation, ensuring the signal integrity of high-speed SIM card communication.

[0052] In one embodiment of this utility model, the device further includes a network status acquisition module and an automatic decision-making module;

[0053] The input terminal of the network status acquisition module is connected to the analog-to-digital converter pin of the control unit to acquire the electrical signal parameters of the network quality of each SIM card.

[0054] The automatic decision-making module is integrated into the control unit. The automatic decision-making module is communicatively connected to the network status acquisition module and the data storage. The automatic decision-making module outputs a switching command to the control terminal of the gating switch group.

[0055] In critical applications such as Industrial Internet of Things (IIoT), remote monitoring, and mobile payment, network outages mean business interruptions and economic losses. Traditional solutions only restore service after a complete disconnection by rebooting. The network status acquisition module, connected to the ADC pin of the control unit, continuously converts analog signals representing network quality into digital parameters. The automatic decision-making module analyzes these parameters in real time using software algorithms and compares them with preset strategies and user habit records stored in memory to generate switching commands. This solves the pain point of users having to manually judge network quality and perform switching operations, achieving fully unattended automated network optimization. This embodiment can trigger switching actions in the early stages when network quality begins to deteriorate but has not yet completely disappeared, maximizing the seamless connection of wireless communication links and service availability.

[0056] In one embodiment of this invention, a status indicator light is also provided, which is connected to the microprocessor. The status indicator light uses different colors, such as green, red, and blue, and flashing frequencies, such as constant / slow flashing / fast flashing, or multiple combinations thereof, to transform these internal states into intuitive states, providing users with intuitive and immediate visual feedback on device and network status, greatly enhancing the human-computer interaction experience. For example, when the device malfunctions, such as a SIM card not being recognized, switching failure, or network registration timeout, the microprocessor can control the indicator light to enter a specific fault code indication mode, such as flashing red three times, pausing, and repeating, etc.

[0057] Implementation Case 1:

[0058] A SIM card hub device includes: a replacement contact, a microprocessor, a switching module, three expansion slots (Slot A / B / C), a signal path, a first power supply path, and a second power supply path, with the specific structure as follows:

[0059] Replacement contact: Inserted into the original SIM card slot of the terminal, it connects to the terminal's cellular module and is used to receive power from the terminal and transmit signals;

[0060] Microprocessor: It adopts an ARM Cortex-M0 core, draws power from the terminal through the first power supply path, and controls the switching module and the second power supply path;

[0061] Switching module: includes two cascaded SPDT (single-pole double-throw) switches (K1 / K2), K1 selects the input of Slot A or K2, and K2 selects Slot B or Slot C to achieve three-slot switching;

[0062] Expansion slots: Three Nano SIM card slots, supporting hot-swapping, with built-in ESD protection circuitry in each slot;

[0063] Power supply path: The first path supplies power to the microprocessor, and the second path supplies power to the selected SIM card through a soft-start circuit to avoid current surges;

[0064] Signal path: Differential signal transmission is used, supporting LTE Cat.12 rate, and integrated impedance matching circuit.

[0065] process

[0066] Trigger signal processing: The microprocessor receives switching instructions sent by the terminal (such as manual triggering by the user or automatic policy triggering) through the UART interface, and controls the switching of K1 / K2 after parsing the instructions;

[0067] Beneficial effects

[0068] Enhanced scalability: Supports "one-to-three" expansion to meet the network access needs of multiple operators and scenarios;

[0069] Battery-free design: powered by the terminal, reducing size by 40% and cost by 30%;

[0070] High compatibility: Adapted to Android / iOS systems and supports 5G NSA networks.

[0071] (I) Hardware Implementation

[0072] Replacement contact: Made of 0.1mm stainless steel with gold-plated contacts, corresponding one-to-one with the pins of the terminal's SIM card slot, supporting 1.8V / 3V SIM cards;

[0073] Microprocessor: STM32L051C8T6, operating frequency 32MHz, built-in 128KB Flash, supports low power mode, and communicates with the switch via I2C interface;

[0074] The switching switch uses TI's TS3A24159 chip, with an on-resistance of ≤5Ω, a switching time of ≤10ns, and supports hot switching.

[0075] Power supply path: The first path converts the terminal's 5V input to 3.3V for the microprocessor via a DC-DC converter; the second path uses an RT9193 soft-start chip to achieve a gradual voltage change from 0 to 3.3V, avoiding power surges on the SIM card.

[0076] 1. Initialization process

[0077] After the terminal is powered on, the replacement contact plate supplies power to the microprocessor through the first power supply path, and the microprocessor initializes the UART (baud rate 115200), I2C interface and GPIO pins;

[0078] The system scans the three expansion slots, detects whether the SIM card is in place via the ATR (Reset Response Signal), and stores the card information (ICCID, carrier) in the E2PROM.

[0079] Switching process

[0080] When a user selects the target SIM card (e.g., Slot B) in the terminal APP, the terminal sends the command "AT+SWITCH=B" via UART.

[0081] After the microprocessor parses the instructions, it controls K1 to switch to K2, K2 to switch to Slot B, and simultaneously supplies power to Slot B through the second power supply path;

[0082] The microprocessor returns "OK" to the terminal, and the terminal's cellular module re-registers with the network, completing the handover.

[0083] In summary, any other corresponding modifications made by those skilled in the art after reading this utility model document, based on the technical solution and concept of this utility model without creative mental effort, shall all fall within the scope of protection of this utility model.

Claims

1. A SIM card hub device based on a one-to-three architecture, characterized in that, Includes connectors, control units, strobe switch groups, multiple SIM card interfaces, signal transmission paths, and power management circuitry; The connector is matched and connected to the SIM card slot interface of the mobile terminal; The connector is connected to the power supply terminal of the control unit through the power supply branch of the power management circuit; the connector is also connected to the access port of the gating switch group through the signal transmission path. The gating switch group includes two cascaded gating switches, and the access port of the gating switch group is connected to the signal transmission path; wherein, one gating port of the first-stage gating switch is directly connected to a first SIM card interface, and the other gating port is connected to the access port of the next-stage gating switch; each gating port of the final-stage gating switch is connected to a different SIM card interface. The control signal output terminal of the control unit is connected to the control terminal of the gating switch group; The input terminal of the power supply branch of the power management circuit is connected to the connector.

2. The SIM card hub device based on a one-to-three architecture according to claim 1, characterized in that, The power supply branch of the power management circuit integrates a soft-start circuit. The enable terminal of the soft-start circuit is connected to the control unit. The control unit controls the soft-start circuit to output a power supply signal to the SIM card, in which the soft-start circuit voltage gradually increases from zero to the rated operating voltage.

3. A SIM card hub device based on a one-to-three architecture according to claim 2, characterized in that, The soft-start circuit includes a linear regulator, the enable pin of which is connected to the GPIO pin of the control unit. The control unit outputs a pulse width modulation signal through the GPIO pin to control the output voltage of the linear regulator.

4. A SIM card hub device based on a one-to-three architecture according to claim 1, characterized in that, Any of the gating switches in the gating switch group is a single-pole double-throw analog switch, and the on-resistance of the gating switch is less than 10 ohms.

5. A SIM card hub device based on a one-to-three architecture according to claim 1, characterized in that, The control unit is a microcontroller based on the ARM Cortex-M0 core, and the microcontroller communicates with the control terminal of the gating switch group via an I2C bus or an SPI bus.

6. A SIM card hub device based on a one-to-three architecture according to claim 1, characterized in that, It also includes a memory, which is electrically connected to the control unit, and is used to store the identification information and status flags of the SIM cards connected to each SIM card interface.

7. A SIM card hub device based on a one-to-three architecture according to claim 1, characterized in that, At least one of the plurality of SIM card interfaces is a Nano-SIM card socket, and the Nano-SIM card socket is connected in series with an ESD protection device.

8. A SIM card hub device based on a one-to-three architecture according to claim 1, characterized in that, The gating switch group consists of two cascaded single-pole double-throw switches, and the number of the multiple SIM card interfaces is three; The moving end of the first-stage single-pole double-throw switch is connected to the signal transmission path, the first stationary end of the first-stage single-pole double-throw switch is connected to the first SIM card interface, and the second stationary end of the first-stage single-pole double-throw switch is connected to the moving end of the second-stage single-pole double-throw switch. The first stationary terminal of the second-stage single-pole double-throw switch is connected to the second SIM card interface, and the second stationary terminal of the second-stage single-pole double-throw switch is connected to the third SIM card interface.

9. A SIM card hub device based on a one-to-three architecture according to claim 1, characterized in that, The device also includes a network status acquisition module and an automatic decision-making module; The input terminal of the network status acquisition module is connected to the analog-to-digital converter pin of the control unit to acquire the electrical signal parameters of the network quality of each SIM card. The automatic decision-making module is integrated into the control unit. The automatic decision-making module is communicatively connected to the network status acquisition module and the data storage. The automatic decision-making module outputs a switching command to the control terminal of the gating switch group.

10. A SIM card hub device based on a one-to-three architecture according to claim 5, characterized in that, It also features status indicator lights, which are connected to the microprocessor.

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