4 different applications with the same device! 4 port (FXS & FXO) POTS Telephone line over LAN (Ethernet & IP) converter can work in 4 different network applications. First, you can use it as 4 FXS/FXO over Ethernet device – it will work over a simple network hub or router within the same network subnet. Units will come with pre-configured IP addresses so that you can just simply plug in your phones (and even fax) on one side, and connect to the CO side – PABX, on another side, and it will work right out of the box. Need to change IP addresses? You can do so via the web manager. Or another application is simply connecting uplink ports LAN1 or LAN2 via Ethernet cable directly - in this case, the device will work as voice ports over the same RJ-45 cable, just keep in mind a maximum distance of 100m. Then another application you can think of is to use FX uplink port. In this case, just use a 155M (Fast Ethernet) SFP module transceiver (does not come in this set) and you can connect the uplink port now to any fiber optic Ethernet switch. In this case, check that fiber transceiver parameters match exactly. Even if you have a simple fiber optic cable run, and want to send the FXS/FXO POTS voice traffic over it – then as well – just install 2 matching SFP 155M (100FX) transceivers into the FX ports, and simply connect to fiber at both sides. Specifications FXS & FXO Phone Interface Ring voltage: 75V Ring frequency: 25HZ Two-line Impedance: 600 Ohm (pick up) Return loss:40 dB Ring detect voltage: 35V Ring detection frequency:17HZ-60HZ Ethernet Interface (10/100M) Datarate: 10/100Mbps, half/full dpx Compatible with IEEE 802.3 Connector: RJ45 (SFP) Interface datarate:155Mbps Power supply: AC90V ~ 265V Power consumption: ≤7W Working temperature:-10°C ~ 60°C Humidity:5%~95 % Dimensions: (216 L) X 140 (W) X 31 (H) mm