Swisscom will switch off its 3G network at the end of 2025. This 3rd generation of mobile communications was introduced 20 years ago and has become inefficient in terms of energy requirements, spectrum usage and the resources required to maintain it, so operators are freeing up these resources for new technologies.

To continue using your mobile phone at CERN (in Switzerland and in CERN’s underground facilities) you’ll need a device that supports at least 4G and VoLTE (Voice over LTE). SMS (Short Message Service) services will be maintained via 4G.

You can check your device’s compatibility via Swisscom’s cockpit or by sending a free SMS to 444, using your CERN SIM card, with the keyword 3G. Please be aware that some models' characteristics are not properly identified in Swisscom's database. If this is the case, you should check that 4G/5G is shown on your phone as an option for data connectivity. You will also need a VoLTE-compatible phone to place/receive calls. If your device displays 4G but it disappears when you make a call (while connected to Swisscom), then VoLTE is not switched on or your device is not compatible.

If your phone is not compatible, you should replace it. 4G and VoLTE have been standard on mobile phones for the last 7 to 10 years, depending on the brand.

For further information, you can visit this link or contact the mobile service support team.