FXS Voice over IP series is two-port/four-port telephone extension to IP network gateway and supports H.323 v2/v3/v4 or SIP RFC 3261protocol. It provides telephone services and T.38 fax over IP network with easy operation and configuration for ITSP / ISP (Internet Telephony Services Provider) and Office / SOHO IP-PBX application. You can use FTP/TFTP to perform configuration backup/restore and firmware upgrade for the FXS Gateway from a remote location. Moreover, the embedded web configuration allows you to use a web browser to manage the FXS Gateway.