1) wireless doorbell with audio intercom, 2) DECT, cordless telephone, 3) Unlock module, 4) Frequency: 1. ... supply: Indoor unit: Adapter (Input: AC110~230V +/-10%, 50-60Hz)Outdoor station: 2 C size alkaline batteries Features1,Support all DECT ... phone features2,Use the handset to talk with outdoor station3,Use the handset to unlock the door (optional)4 ...