Settings > Call Signalling > Function Key for Call Signalling by Flashing Display Backlight

Function Key for Call Signalling by Flashing Display Backlight
Press the key while in the telephone's idle state to switch call signalling by the flashing display backlight 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 1600 - Firmware V2.2 - COMfortel Set V3.16 - Advanced Information V10 02/2019