Manufacturers Description With the BT Graphite 2100 DECT telephone you can cut your phones running costs by up to half with its energy efficient power supply. The power supply unit is specifically designed to use up to half the amount of energy compared to previous models non ECO models. Other features to those listed include: conference call, call transfer & internal calls, all on multi packs, 5 standard handset ringtones, handset ringer on or off, handset ringer volume control, associated ringtone, 5 base ringtones, base ringer on or off, base ringer volume control, auto answer, secrecy function, handset naming, keypad lock, earpiece volume control, handsfree volume control, call timer, clock, alarm, keypad confirmation tone, low battery indicator, low battery alert, out of range alert, upto 10 hours talktime & upto 100 hours standby time. For caller display or call waiting features you must subscribe to a caller display or call waiting service for these features to work. Your network provider may charge you for these services.