Settings > Receiver and Headset > Function Key for Headset Operation

Function Key for Headset Operation
Press the key to switch headset operation on or off or to switch it over.
In addition the status of the function is indicated by the corresponding LED.
 
Note: When functions are defined on the second key level (optional, see Technical Data in the Instructions), LED signalling is not available.
 
Proceed as follows by assigning the function key:
Note: For further information about the general procedures when assigning function keys, see Function Keys.
 

COMfortel 1400 - Firmware V2.2 - COMfortel Set V3.16 - Advanced Information V07 02/2019