The difference between DE and International lies in the DSL modem, so it is only relevant if the FritzBox is to be operated with the built-in DSL modem on a Swiss DSL connection. The DE versions are only capable of DSL Annex-B, whereas in Switzerland Annex-A is used on analogue telephone connections and Annex-B on ISDN connections. In addition, AVM provides the DE versions better with new firmware versions (the new versions arrive, if at all, with a very long delay on the international version). The international versions allow a choice between Annex-A and Annex-B in the initial setup.
Unfortunately, I cannot say whether anything has changed here with the switch-off of ISDN and the switchover from analogue telephony to all-IP connections. Ultimately, Annex-A offers greater bandwidth and therefore more performance, which is why I believe that Annex-A will continue to be the standard DSL frequency coding in Switzerland. I myself use the box behind a cable modem, so I am independent in this respect. The DE version can of course also be used behind a "dumb" DSL modem or a DSL router that is operated in bridge mode.
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https://praxistipps.chip.de/annex-a-od...