AVM FRITZ!Box Fon Internet Telephony and ADSL Web Surfing in One. You can make Voice-over-IP phone calls over the Internet using your existing analog telephones. Simply connect your phones to the extension lines of the new FRITZ!Box Fon. Features: Use existing phones both for conventional lines and for Internet telephony. High voice quality through intelligent bandwidth management. Combined ADSL modem and ADSL router for fast access from multiple PCs. High-security firewall with port forwarding and IP masquerading.