FXO stands for foreign exchange office. An FXO port is an interface that connects your Plain Old Telephone Service (POTS) line to a VoIP adapter. Traditional telecom operator phone lines or analogue PBXs are connected to IP telephony networks using FXO VoIP Gateway, which offer 4, 8, and 16 FXO ports. The FXO gateway has FXO ports, which are used to connect the PBX system to the gateway, and VoIP ports, which are used to connect the gateway to the VoIP system. The FXO Gateway acts as an interface between the PBX system and the VoIP system, allowing users to make and receive calls using their traditional analog phones while taking advantage of the cost savings and other benefits of a VoIP system.

FXS stands for foreign exchange subscriber. An FXS port is an interface that connects station devices such as your phones or PBX to a VoIP adapter. The FXS VoIP Gateway are cost- effective, dependable VoIP gateways that seamlessly connect analogue phones, fax machines, and legacy PBX systems with IP PBX systems and IP Phone networks, allowing you to leverage your existing telephony infrastructure and simplifying your VoIP migration. The DAG series of gateways, which span from 1 to 128 FXS ports, 4 to 32 FXO ports, and hybrid 4FXS4FXO, 8FXS8FXO, has been widely adopted by telecom operators, service providers, and businesses.