FRITZ!Fon C4 Service - Knowledge Base
Using a headset
In addition to using the "hands-free calling" function to make calls with your FRITZ!Fon, you can also use a headset with it. The telephone has a 3.5 mm stereo jack on its right side.
You can use any commercially available headset for mobile telephones with an earphone impedance of 32 Ohm and a microphone impedance in the range of 800-2200 Ohm (+/- tolerance). You can use stereo or mono headsets with the connector pin assignment shown below. The mechanical protection of the connector should be no more than 7 mm in order to ensure good contact.
Fig.: Assignment of the 3.5 mm jack (stereo)
Fig.: Assignment of the 3.5 mm jack (mono)