To prevent the other party from listening in while you consult with someone in your office, you can temporarily switch off the handset microphone or the handsfree microphone. You can also switch on the handsfree microphone to answer an announcement via the telephone speaker (speaker call, ). 

Speakerphone mode is not available with optiPoint 400 economy.

Precondition: You are conducting a call. The microphone is switched on. 

Press the key. The LED lights up. 

Press the illuminated key. The LED goes out. 

Select and confirm. 

Press the key. The LED lights up 

Enter the code for "on or "off".