VoIP trunk gateways connect an IP network to POTS (plain old telephone service) analog lines to send IP voice and data to the conventional phone sets and fax machines. Designed as a cost-effective VoIP solution for a small to medium-sized business and the branch office, these devices provide 4 or 8 FXO (Foreign eXchange Office) ports for 4 or 8 phone line connections. IP network connection can be through any of the 4 LAN ports or the WAN port (all 10/100BASE-TX Ethernet interfaces).