In IoT Connectivity, SIM Cards often roam across networks in other countries giving them the ability to connect to more than one single network. The key advantage to connecting in this way is that there are often multiple networks available, via roaming partners, depending on the way the SIM is configured. Switching between networks often requires no intervention from an end user (which is optimal for IoT Connectivity). This brings about a few more ways in which SIM cards work.
Multi network vs single network SIM cards A single network SIM card is often provided by a local network operator and has access to that specific network, like a Vodafone SIM in the UK that connects to the Vodafone network. This SIM may be able to roam on different networks in other countries where Vodafone is not available (provided your tariff allows and roaming agreements are in place with the networks).
Almost all traditional mobile SIM cards are single network SIM cards, but some IoT SIM cards could be single network SIM cards too such as a Telefonica (O2) SIM from Spain that is being used in the UK but only has access to the O2 Network, even though Telefonica have roaming agreements in place with other UK networks. The communication plan (the agreed network & technology parameters on which the SIM card operates) allows the SIM to only connect to the O2 network, making the SIM more cost effective and thus a single network SIM card.
With multi network SIM cards, SIMs will have access to more than one network in the country it is being used in. In IoT connectivity, most SIM cards have a fixed originating country but roam on other networks unlike standard consumer mobile SIM cards that typically have one single fixed network.
Let us imagine a European SIM provider which has access to the local European network as well as multiple roaming options in other parts of the world. This SIM can be used in the UK and has access to the O2, Vodafone, 3 (Hutchinson) and EE as the network will have roaming agreements in place for all UK networks. The total area covered by all mobile networks is much larger than that of any single network. The networks above could be Vodafone, EE, O2 and 3, for example, when using a multi network SIM in the UK.
It is important to remember that a SIM can only ever be connected to one network at time even though the SIM has access to multiple available networks.
The SIM manufacturer or the SIM form factor do not determine if it is a Single Network or multi network SIM card, a SIMs communication plan (or Tariff) determines if the SIM is multi network or single network Steered vs unsteered roaming SIM cards
When using multi network SIM Cards, there are two types of roaming that suppliers can configure, steered roaming or unsteered roaming. Unsteered SIMs offer connectivity to any network with a signal.
If there are two or more networks in range, then they will connect to either network (depending on the parameters set on the IoT device).
The SIM will often remain connected to the network it initially connects to unless:
- either the device is rebooted to initiate a re-scan of available networks
- the device is prompted to initiate a re-scan of available networks
- the current network is lost, and the device initiates a rescan of available networks.
An unsteered SIM card will have no network preference. If the device that the SIM is inserted in has no intelligence to run a network scan or any rules configured, it will select the first network it detects as its home network, regardless of signal strength and network technologies. This article was written by our team of IoT experts here at Fidelity Group. We support a wide range of business sectors with our outstanding IoT solution, which includes our market-leading software management platform, vM2M. If you would like to speak to one of our experts to find out how we can help your business, please Click here or call us today on 0800 840 6800.
