Resilient SIM: smarter cellular network selection for Ajax hubs

Cellular connectivity doesn't always fail loudly. Sometimes, a signal looks strong, yet data transmission remains unstable. Resilient SIM is a new Ajax SIM feature designed to improve cellular reliability in these situations.

Resilient SIM overrides the modem's default network selection logic. The feature allows an Ajax system to prioritize cellular networks based on performance to maintain reliable communication at all times.

Let's take a closer look at how it works.

The feature is available for Ajax hubs with Ajax SIM installed and activated.

The limits of default modem logic

Most modems automatically connect to the network they determine best. Usually, this decision is based on signal strength, availability, and connection history. In theory, this makes sense. In real-world conditions, it often doesn’t.

Signal strength and network visibility do not always equal a reliable connection for a hub. There might be provider-side issues that the cellular modem can neither detect nor fix. For example, during network maintenance, cell base towers keep working as usual, but data services remain temporarily unavailable. In such a case, the hub simply cannot come online.

For installers, this often results in frustrating situations where the hub repeatedly reconnects to the same problematic network, even after a reboot, even though nearby networks would perform better in practice.

How Resilient SIM works

Resilient SIM enables the system to bypass the limitations of modem network priorities and change how a cellular network is selected. The hub can switch from a technically preferred network to an alternative that delivers more stable connectivity in practice — even if it has a lower priority or a weaker signal.

With Resilient SIM, the hub can: