Analog VoIP gateways are small stand-alone appliances that allow you to convert voice media between FXO and FXS connections and VoIP connections. They are the most cost-effective solution for businesses with a legacy phone system infrastructure that want to connect to a VoIP network, such as a SIP trunk. They are also great for businesses with an IP-based phone system and need to connect legacy equipment to their IP network, such as analog phones, traditional fax machines, and the PSTN for emergency fallback.