FRITZ!Fon C4 Service - Knowledge Base

FRITZ!Fon C4 Service
Not your product?
This document is also available for the following products:

FRITZ!Fon keeps turning off suddenly

Now and again, the FRITZ!Fon suddenly turns off, for example during telephone calls. The telephone does not restart; you must press the end call key to turn it on again.


  • The rechargeable battery is not charged enough or is defective.

Simply proceed as described below. After each measure, check whether the problem persists.

1 Charging the battery

  1. Leave the telephone in the charging cradle for at least 6 hours to completely charge the rechargeable battery. Make sure that the symbol for "Charging battery" appears on the display of the telephone.

2 Replacing the rechargeable battery

You can purchase a genuine replacement battery from an electronics retailer. Using so-called aftermarket batteries that are not originals, like the kind available over the internet, may damage your FRITZ!Fon.

Important:Rechargeable batteries wear out because they are subject to a natural aging process as physical and chemical changes occur within the battery; this is why they are not covered by the warranty (see warranty in the manual).