物联网SIM卡断开连接的6大核心原因

For businesses relying on Internet of Things (IoT) devices—whether smart meters, logistics trackers, or industrial sensors—sudden IoT SIM card disconnection is far from a trivial issue. It can directly lead to operational disruptions, loss of critical data, and even cascading financial losses. As the scale of IoT deployments expands, "why does my IoT SIM card lose network" has become a frequent question in enterprise operations and maintenance. This article details the 6 core causes of IoT SIM card disconnection, helping you quickly identify problems and minimize downtime.

This is the most common cause of IoT SIM card disconnection, rooted in the fact that IoT devices often operate in scenarios beyond the signal coverage of consumer-grade mobile phones. On one hand, many devices need to run in remote areas where the density of cellular base stations is low. Signal transmission is easily blocked by terrain, resulting in weak or even no signal. On the other hand, some devices are deployed in enclosed spaces—concrete walls and metal structures severely weaken signal penetration. Even if the base station is not far away, it is difficult to establish a stable connection. Additionally, electromagnetic interference exacerbates the problem: large motors in factories, for example, emit electromagnetic signals that interfere with cellular network frequency bands, causing frequent interruptions in communication between the IoT SIM card and the base station.

The Access Point Name (APN) is the "bridge" connecting IoT devices to the carrier’s data network. It defines the path, protocol type, and authentication method for the device to access the network. Once there is an issue with APN settings, the IoT SIM card cannot establish an effective data connection even with full signal. Common error scenarios include: first, typos during manual entry, which prevent the system from recognizing the correct path; second, using the wrong type of APN—for instance, replacing the APN dedicated to industrial-grade IoT with a general APN for regular mobile phones. The two differ in network permissions and data transmission priority, leading to rejection of access by the carrier; third, outdated APN parameters. Some carriers adjust APN configurations due to network upgrades. If the device fails to update synchronously, the old parameters become invalid, resulting in connection failure.

IoT SIM卡在长时间暴露于恶劣环境或不当操作时容易发生硬件故障。故障主要分为三类：第一，物理损坏——设备的SIM卡槽变形或SIM卡芯片划伤；第二，环境侵蚀——户外环境中雨水渗透导致芯片腐蚀，或工业环境中油污附着在SIM卡表面，妨碍与卡槽的接触；第三，极端温度影响。在低于-40°C或高于85°C的环境中，SIM卡的芯片材料因热膨胀和收缩而失效，导致无法正常读取数据。此外，一些低成本的SIM卡存在质量缺陷，可能导致接触不良。

Even if the IoT SIM card and the device itself are in good condition, fluctuations in the external network environment can cause disconnection. Network congestion mostly occurs in high-density scenarios. During peak hours, a large number of devices send data simultaneously, leading to saturation of the carrier’s base station bandwidth. Some devices lose network because they "cannot compete" for network resources. Carrier outages are uncontrollable factors, which may result from base station hardware failures, network upgrade and maintenance, or interruptions caused by force majeure (such as heavy rain or earthquakes). The characteristic of this type of disconnection is "regional"—multiple devices under the same carrier’s coverage experience issues at the same time, and the disconnection duration matches the outage duration.

The firmware and supporting software of IoT devices are the "invisible support" for ensuring the normal network connection of IoT SIM cards. Once vulnerabilities occur, they directly affect connection stability. You can troubleshoot technical issues one by one, such as compatibility of firmware versions, configuration conflicts in software, and whether security vulnerabilities have been attacked. Additionally, if the device’s firmware is not updated for a long time, old vulnerabilities will accumulate, and the probability of disconnection will increase with usage time.

To access the carrier’s network, an IoT SIM card must undergo strict identity authentication. This process relies on core credentials built into the SIM card—International Mobile Subscriber Identity (IMSI) and Authentication Key (Ki). Once there is a problem in the authentication process, the connection will be directly rejected by the carrier. It is also necessary to continuously monitor the validity period of the credentials to avoid being deemed invalid due to expiration. Furthermore, the use of the SIM card must comply with the carrier’s regulations. If the carrier detects "abnormal usage" of the SIM card, it will temporarily block the SIM card to prevent risks, prohibiting it from accessing the network.

Metrix Aero Core, 在物联网行业排名前十，与多个国家和地区的运营商保持紧密的战略合作。它提供多种解决方案，以应对运营商的动态变化，为客户的物联网网络的稳定性提供全天候保护。

If you are looking for reliable IoT SIM card solutions to reduce disconnection risks, or need professional support for IoT network maintenance, Metrix Aero Core can be your trusted partner.