You can activate or deacticate ringing on your NEC DS series phone using the folowing procedure:

To turn ringing on and off (for line, Call Coverage, and Group Call Pickup keys):

1. Do one of the following:
   - For line keys, dial #RAL (#725).
   - For Call Coverage keys, dial #RAC (#722).
   - For Group Call Pickup keys, dial #RAP (#727).
2. Press the key to change the ringing. The flash rate shows you the ringing mode.
   - On green for Immediate Ring.
   - Slow flash green for Night Ringing (line keys only).
   - Fast flash green for Delayed Ringing.
   - On red for no ringing.
3. Press SPEAKER to exit.