App Fon, it's easy to connect your cell phone or tablet to your FRITZ!Box via wireless LAN and use it as a landline phone. This allows you to conveniently make. With a huge range of features, the Fon WLAN isn't your average router. As well as ADSL2+, there's support for ISDN, VDSL2, cable. We don't often get excited by a wireless router, but when German firm AVM brought its Fritz!Box ADSL2+ router into the office for a demo.