Newly arriving Wireless Video Door Phone,2.4G lauch frequency,Power just 20dbm,remote control around 150-180M. Wireless Video ... :TH-09E77Features OF Wireless Video Door Phone: >2.4G lauch frequency, the power is no more than 20dbm, non-obstacle remote ... phone;>Clear night-viewing, 24 hour monitoring, calling , speaking and unlocking remote controlling, etc; >One indoor video phone can control 1 ...