... SMS;7. Handsfree, Redial, Call transfer and SMS function;8. Ringer volume adjustable;9. Call waiting, DND calendar, Alarm Clock;10 ... used as a moderm;12. Rechargeable backup battery;13. Video door phone system;Specifications:1. Frequency range: GSM 900/1800MHz; GSM ... . Colors: White, Black, Blue etc. selectable; 3G WCDMA UMTS VIDEO DOOR PHONE SYSTEM