1. What is an eSIM?

An eSIM (embedded SIM) is a SIM that is built directly into a cellular device, rather than being inserted as a removable SIM card.

Like a physical SIM, an eSIM stores the subscriber identity and authentication information required for the device to register and authenticate with a mobile network. Once registered, the device can establish a cellular connection using the network technologies supported by its modem.

The main difference is how the SIM is integrated and managed. A physical SIM must be inserted into a SIM slot and physically replaced when required. An eSIM is integrated into the device and can use connectivity profiles that are provisioned and managed electronically.

From the device's point of view, the basic cellular connection process remains the same: the modem searches for an available network, the SIM provides the credentials required for authentication, and the network determines whether the device is allowed to register.

An eSIM does not, by itself, determine the cellular technology or coverage available to the device. These depend on the device modem, supported frequency bands, the connectivity profile and the mobile networks available in the deployment location. 

2. Physical SIM vs eSIM

Physical SIMs and eSIMs perform the same core function: they provide the subscriber identity and authentication information required for a device to register on a mobile network.

The main difference is how the SIM is integrated into the device and how connectivity profiles are managed.

	Physical SIM	eSIM
Form	Removable SIM card	Integrated into the device
Installation	Inserted into a physical SIM slot	No physical installation required
Replacement	SIM card must be physically replaced	Does not require replacing a physical card
Connectivity profile	Typically associated with the inserted SIM	Can be provisioned and managed electronically
Deployment	SIM sourcing, installation and handling may be required	Can reduce physical SIM handling during deployment
Network access	Uses SIM credentials to authenticate with the mobile network	Uses SIM credentials to authenticate with the mobile network

 From a cellular network perspective, both perform the same fundamental role. Using an eSIM does not mean that the device uses a different cellular network or has better coverage than a device using a physical SIM.

3. How does an eSIM work?

An eSIM works with the device's cellular modem to authenticate and register the device on a mobile network.

The eSIM contains a connectivity profile with the subscriber identity and authentication credentials required to access the mobile network. When the device needs to establish a cellular connection, the process typically follows these steps:

1. Network search
The cellular modem scans for available mobile networks using the cellular technologies and frequency bands supported by the device.

2. Network selection
The modem selects an available network that is compatible with the device and permitted by the connectivity profile. When roaming is supported, this may include networks operated by roaming partners.

3. Authentication and registration
The eSIM provides the subscriber credentials required to authenticate with the selected mobile network. If authentication is successful and the network permits access, the device registers on the network.

4. Cellular data connection
Once registered, the modem can establish a cellular data connection using the device's configured network settings.

5. Data communication
The device can then send and receive data through the mobile network to its configured server or platform.

4. Where does an eSIM work?

An eSIM can operate anywhere the device and its connectivity profile are supported by an available mobile network. Using an eSIM does not automatically mean that a device has global coverage.

Whether a device can establish a cellular connection in a particular country or location depends on several factors:

Cellular technology
The device modem must support a cellular technology available on the local network, such as LTE.

Frequency bands
The device must support at least one of the frequency bands used by the available mobile network. eSIM functionality does not change the frequency bands supported by the device hardware.

Connectivity profile
The eSIM profile determines which connectivity service the device uses and which networks it is permitted to access.

Operator and roaming agreements
When a device is deployed outside its home network, connectivity may depend on roaming agreements between the connectivity provider and local mobile network operators.

Local network coverage
Even when a country and operator are supported, actual connectivity depends on network coverage at the device's deployment location.

Checking coverage for a Digital Matter device

For Digital Matter devices with integrated eSIM connectivity, always refer to the product-specific documentation before deployment. Supported countries, operators, cellular technologies and network settings can vary between device models and regions.

5. eSIM in Digital Matter devices

Digital Matter devices may use either a physical SIM or an integrated eSIM, depending on the device model and regional variant.

For devices supplied with an integrated eSIM, the connectivity profile and required network settings may be preconfigured as part of the device setup. This reduces the need to source, install and configure a physical SIM before deployment.

The specific connectivity available to a device depends on its hardware, regional variant and the connectivity service provisioned on the eSIM. For this reason, supported countries, networks and configuration requirements should always be checked against the documentation for the specific device.