Two connections are established for each call with an IP phone on the 'LAN/WAN' port.

Therefore, you can only conduct up to four internet calls concurrently with IP phones. Additionally, the total number of possible calls is reduced.

Examples:
An IP phone is being used to conduct an internet call and another IP phone is being used for a landline call. Then five additional internet calls can be made using the other interfaces.
Internet calls are being conducted with two IP phones. Then four additional internet calls can be made using the other interfaces.
Internet calls are being conducted with four IP phones. Then no additional internet calls can be conducted using the other interfaces.

Via the landline and/or the internet you can conduct up to three calls simultaneously with cordless phones that are registered with the FRITZ!Box.

Examples:
Internet calls are being conducted with three cordless phones and an IP phone. Then three additional internet calls can be made using the other interfaces.
Internet calls are being conducted with three cordless phones and two IP phones. Then one additional internet call can be conducted using the other interfaces. No additional call can be conducted with an IP phone.

You can conduct one call with each analogue device connected to the 'FON 1' or 'FON 2' socket.

Up to two calls can be conducted at the same time via the landline and/or the internet with ISDN devices connected to the 'FON S0' socket.

The answering machine and the fax can each accept one call. All other callers hear a busy signal, even if you set up more than one answering machine. You cannot send a fax while receiving a fax, and you cannot receive a fax while sending one.