See also:

Calls with multiple parties
General information You can switch between calls or connect two calls to a single conference call. These functions must be supported by the mobile phone and service provider. Accepting a call ...

Deleting the button assignments
1. Press buttons 1 and 8 simultaneously for approx. five seconds. 2. "OK" ...

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. ...