ClearDigital Power Delivers Maximum Clarity & Background Noise Suppression 50 dB amplification with full range tone control Full duplex speakerphone in handset and base DECT 6.0 System expandable up to 5 handsets total (Expansion Handset - A1600E-BT) Talking Caller ID - speaks name and number of caller Why incorporate Bluetooth in a landline phone? Flexibility & freedom. The A1600 with Bluetooth now allows individuals who depend on their mobile phones as their basic communication device, to benefit from the full range of amplification and frequency control, as well as comfort and features that ClearSounds amplified phone have to offer.