... 2.Degree of distortion:below 5%. 3.16-chord ring (BTS-FC36T) handfree indoor video door phone is applicable inside. video indoor phone, indoor phone, indoor phone ... phone, video door phone (indoor phone), indoor video door phone with free hand, video intercom/video door phone/video door entry indoor monitor, indoor video phone, video door phone with indoor unit Features as belows:1.4-inch TFT. 2 ...