Two connections are established when making calls with an IP telephone that is configured for the "LAN/WAN" port. Therefore, you can conduct a maximum of three calls at the same time with IP telephones, and the number of possible calls is reduced.

Example:
If two IP telephones are being used to conduct calls, two additional calls can be made using the other interfaces.
If three IP telephones are being used to conduct calls, no additional calls can be conducted using the other interfaces.

You can conduct a maximum of three calls at the same time using cordless telephones that are registered with the FRITZ!Box's DECT base station.

Example:
If calls are being conducted with two cordless telephones and an IP telephone, two additional calls can be made using the other interfaces.
If calls are being conducted with three cordless telephones and an IP telephone, an additional call can be conducted with an analog telephone, or the integrated answering machine or the fax can accept an additional call. You cannot conduct an additional call with an IP telephone.

You can conduct one call with an analog device connected to the socket "FON".

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 receiving a fax while sending one.