The GXW-4004 is a next generation IP voice gateway that is interoperable and compatible with leading IP-PBXs, SoftSwitches and SIP platforms. The GXW FXS Gateway series is auto-configurable, remotely manageable and scalable. Each model features flexible dialing plans, PSTN failover, integrated call routing to support a pure IP network call and an external power supply. The GXW FXS Gateway series enables small and medium businesses to create seamless office environments, integrate a traditional phone system into a VoIP network, and efficiently manage communication costs. The GXW FXS Analog IP Gateway series has a compact and quiet design (no fans) and offers superb audio quality, rich feature functionality, strong security protection, good manageability, and compelling price-performance ratio. It is auto-configurable, remotely manageable and scalable. It features 4 or 8-port FXS interface for analog telephones, dual routed or switched 10M/100M network ports with integrated router, PSTN life line in case of power failure, and an RS232 serial port for administration. How does it work? The Grandstream 4004 is a full featured, four port FXS gateway compatible with popular SIP-based IP PBX platforms such as Asterisk, Trixbox and others. The Grandstream GXW4004 allows for the integration of up to (4) analog devices such as traditional analog telephones or fax machines. The Grandstream 4004 provides analog digital signal conversion and allows you to use legacy analog devices with IP based systems.