2.11 Sending DTMF signals  
During a conversation you sometimes have to send DTMF signals, such as with a voice server, an 
automated attendant or a remotely consulted answering machine. 
  During a conversation.  
  Use one of the following:  
o  MFcode  
o  Press the star key. 
  Enter DTMF code. 
The function is automatically cancelled when you hang up. 
2.12 Mute, so that your caller cannot hear you  
You can hear your caller but he/she cannot hear you:  
2.12.1 From the set  
  During a conversation. 
   Disable microphone   The key lights up  . 
   Resume the conversation   The key is no longer lit  . 
2.12.2 From the Bluetooth® receiver (Bluetooth® wireless handset)  
   Press the handset volume/mute key (long press).