Settings > Ringtones > Ringer Volume Automatically

Ringer Volume Automatically
You can increase and decrease the ringer volume on the telephone automatically. The telephone starts to ring at the volume you configured and increases/decreases this every 5 seconds by one level until it reaches the maximum/minimal volume.
Constant ringer volume / steady: Selects a steady volume during the entire calling phase.
Increase the ringer volume automatically / autom.increase: Selects an automatic increase in the volume during the calling phase.
Reduce the ringer volume automatically / auto-reduction: Selects an automatic decrease in the volume during the calling phase.
Single tone / single ringtone: Selects a single quiet tone instead of the ringtones configured.
Proceed as follows:
Using COMfortel Set (page Settings/functions > Signalling/ringer, list field Ringer volume)
Using the telephone (menu settings > signalling > ringer volume)

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