Cybermyth: If a telephone call displays a Swiss number, the call is from Switzerland and must be trustworthy.

24.03.2022 - Telephone users have become accustomed to the caller's number being displayed with every call. If the number is stored in the address book, the matching name will also appear. However, many do not know that this number can easily be faked.

In unregulated telephone networks (unlike in Switzerland, where telephone providers are regulated by OFCOM), a caller can use any sender number by using an appropriate program. This method can be used to make arbitrary calls to Swiss landlines, for example. The number defined by the attacker is not checked by the telephone providers, and is instead relayed one-to-one and shown on the display. The use of fake Swiss telephone numbers is also common practice. This does not by any means indicate that the call really comes from Switzerland. There are also call centres that use Swiss numbers but operate from abroad.


  • Do not trust the telephone number displayed.
  • Be particularly sceptical if you are called by someone you do not know, even if they claim to be from well-known companies such as Microsoft.
  • Be sceptical if someone on the phone asks you to do something such as transfer money, provide credit card details and passwords, or allow access to your computer.

Last modification 24.03.2022

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