If there is more than one phone in an office, it is easier to set specific ringtones for every individual. Follow these instruction to set up a ringtone:
Choose the Preferences option using the green ring key and push the central circle to confirm.
Choose which extension line you would like to assign the ringtone to, using the green ring to navigate and central circle to confirm.
Using the green ring navigator you cycle through the different ringtones, pressing 'play' to hear them. Then you can press 'Set' to confirm the ringtone desired.
You can go to previous menus using the backward flash key on the phone.