How the 4G NIC module connects to a SIM card

4G NIC module and SIM card are the key components for mobile terminals to connect to the cellular network. How the 4G NIC module connects to the SIM card is especially important to understand the principle and main purpose. This article will discuss this connection process and the core technology behind it in detail.

1. Basic structure of the 4G NIC module

Сайт 4G NIC module is generally composed of the following parts:

Baseband Processor: undertakes the conversion of radio signals and digital signals.

Radio Frequency Unit (RF Unit): for sending and receiving data signals.

Battery Management Module: manages the power supply for the function.

SIM card jack: for connecting and loading SIM card information.

Antenna Interface: Transmits to an external antenna to enhance signal reception.

The main function of the 4G NIC port module is data network connectivity, allowing devices to transmit data based on cellular networks. This includes accessing the Internet, sending and receiving data, voice calls, etc.

2. Basic structure and function of SIM card

SIM card (Subscriber Identity Module) This is a smart card that stores user identity information. It contains a unique identification number (IMSI), encryption key and other operator information. The main functions of SIM card are:

Store user identity information for network authentication.

Store user information such as contacts, SMS, etc.

Encryption and secure authentication to ensure communication security.

3. 4G NIC module and SIM card connection process

Physical Connection

Slot design: 4G NIC modules are usually designed with a SIM card slot for inserting a SIM card. The design of the slot can be standard size (SIM), micro (Micro-SIM) or nano (Nano-SIM), and the appropriate size is selected according to the needs of the device.

Contacts: The SIM card is connected to the 4G NIC module through metal contact points. These contact points include power, ground, and data transmission lines to provide power and data communication.

Communication Protocols

ISO/IEC 7816 standard: The communication between the SIM card and the 4G NIC module follows the ISO/IEC 7816 standard, which is an international standard for communication between smart cards and card readers. It defines the card’s electrical interface and transmission protocol.

AT Command Set: The 4G NIC module uses the AT command set (Attention Commands) to communicate with and control the SIM card. These commands are used to read SIM card information, perform authentication, manage SMS and data connections, and more.

Authentication and initialization

Power management: When the 4G NIC module is powered on, the power management unit supplies power to the SIM card to start the card’s internal circuitry.

Reset signal: The NIC module sends a reset signal (RESET) to the SIM card to initialize the card and prepare it for communication.

Card Identification: The NIC module reads the SIM card’s unique identification number (IMSI) and other information for user authentication.

Network registration: the network card module uses the information on the SIM card to register with the mobile network, complete authentication and connect to the network.

4. Conclusion

Precise physical connections and communication protocols allow the 4G NIC module to work in concert with the SIM card for data connectivity of mobile devices. Understanding this connection process is important to improve the device and network experience. There are many more areas where the 4G NIC module can play a greater role in bringing more efficient network services.