The iDCS keysets use the "UP" and "DOWN" keys to adjust the ringer volume (push the button up and it will change the ringer status) while the keyset is ringing, the speaker volume while the speakerphone is in use and the handset volume while you are listening.
These three levels will be stored in memory until changed. If background music is turned on at your keyset, the volume keys will also control the level of music.
The volume of pages heard through the speaker of a keyset can be adjusted during a page announcement by using the volume keys. There are 16 levels for each volume setting. The volume of off-hook ring is controlled by a user-programmable setting.
Learn more about Samsung OfficeServ iDCS by checking this Keyset User Guide from Com-unlimited.com.