Usage: Door Model Number: G2B and G3B Color: White and black Place of Origin: China (Mainland) GSM frequency: 850/900/1800/1900MHz Wireless Frequency: 433MHZ is_customized: Yes G2B Languages voice support: English, Russian, Spanish, French, Italy and Czech republic G3B Languages voice support: English, Russian Manual book: English G2B Network: only GSM G3B Network: GSM and PSTN