Grandstream Networks

Founded in 2002, Grandstream Networks is a manufacturer of IP voice and video communications equipment, video surveillance, gateways and analog telephone adapters (ATAs), and Asterisk-based IP-PBX appliances. Grandstream supplies small and medium businesses and consumers with open-standard SIP-based products.
Grandstream Networks is headquartered in Boston, Massachusetts, and has offices in Plano, Texas and Los Angeles, California in the US, and in Casablanca in Morocco, Valencia, Venezuela and Shenzhen, China.
The company's products are listed on its web site.
References.
Grandstream GXV3275 Android Videophone Wins Gold for Unified Communications Innovation at 2014 Golden Bridge Awards
Grandstream UCM6100 series IP PBX Appliance Receives 2014 Internet Telephony Product of the Year Award
Grandstream GXP2200 - Product of the Year, 2012
Grandstream's GXP2200: Just Like Your Android Smartphone
Grandstream Networks GXP2200 Recognized in Best VoIP CPE Category at 2013 ITSPA Awards