Grandstream UCM6204 Innovative IP PBX with 4 FXO and 2 FXS PortsAnalog Telephone FXS Ports: 2 ports (both with lifeline capability in case of a power outage)PSTN Line FXO Ports: 4 portsNetwork Interfaces: Dual Gigabit RJ45 ports with integrated PoE Plus (IEEE 802.3at-2009)NAT Router: Yes (supports router mode and switch mode)Peripheral Ports: USB, ..