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Number of telephony and DECT devices that can be used with the FRITZ!Box

You can use various telephony devices with the FRITZ!Box, for example telephones, fax machines, answering machines, or telephone systems (PBXs). How many devices can be used depends on the type of connection.

If you set up an additional FRITZ!Box as a Mesh Repeater, the number of possible devices increases according to the number possible for that particular FRITZ!Box model.

Note:All instructions on configuration and settings given in this guide refer to the latest FRITZ!OS for the FRITZ!Box.

1 DECT devices

The following DECT devices can be registered with the FRITZ!Box at the same time:

2 IP telephones and IP door intercom systems

You can register up to ten IP telephones (for example FRITZ!App Fon) or IP door intercom systems with the FRITZ!Box.

3 Analog devices

The FRITZ!Box has four sockets for analog devices; you can use two of them, for example for a telephone, fax machine, and/or door intercom system. One "FON 1" socket and one "FON 2" socket must stay free (not allocated):

  • "FON 1" and "FON 2" for devices with an RJ11 plug
  • "FON 1" and "FON 2" for devices with a TAE plug

4 ISDN devices

You can use an ISDN distributor or S0 bus cabling to connect up to eight devices, for example a telephone or telephone system, at the same time to the "FON S0" socket on the FRITZ!Box. The FRITZ!Box can provide power to one ISDN device, but the other ISDN devices must use their own power supply.

You can use the following ISDN service indicators with devices connected to the "FON S0" socket:

  • Voice (service indicator 1)
  • Data (service indicator 2)
  • Audio 3.1 (service indicator 4)
  • Telephony (service indicator 16)
  • Fax G2/G3 (service indicator 17)

5 Integrated answering machine and fax function

You can use the FRITZ!Box as a fax and answering machine, without having to connect any additional devices. The FRITZ!Box can be used to send and receive faxes and you can configure up to five different answering machines.