Connect your analog devices to your IP phone system. The Fanvil G100S gateway supports up to one SIP server in SIP 2.0, correlative RFCs. The Fanvil G series are VoIP analog telephone adaptors (ATA) used for connecting analog devices such as phones and fax machines to an IP phone system. About Fanvil Technology Co., Ltd Fanvil Technology Co., Ltd. is a professional developer and manufacturer of VoIP products. Fanvil provides VoIP communication devices solutions for small and medium sized businesses, as well as large mission-critical enterprise environments.