See also:

Connecting headphones
You can connect headphones with a jack plug or operate them using the infrared interface. To enable optimal use of the infrared interface, use infrared headphones that comply with the IEC 61603 ...

DTMF suffix dialing
DTMF suffix dialing can be used for gaining access to network services or for controlling devices, e.g., to make a remote inquiry of an answering machine. The DTMF code is needed for this purp ...

Switching the microphone to mute
When a call is active, the microphone can be muted. 1. "Telephone". 2. "Active calls". 3. "Microphone mute" A microphone that has been switched to mute is automa ...