See also:

Setting the language
Press the adjustment button for 12‑13 seconds. Briefly press the adjustment button again to switch between English "E" and German "O". The setting is automatically saved ...

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 ...

Reference
This chapter contains technical data, short commands for the voice activation system, and an index that will quickly take you to the information you need. ...