What is FXS, a Professional Explanation on Foreign eXchange Subscribers and their Use

FXSs or Foreign eXchange Subscribers are those plugs on the wall, from where the cable runs towards an FXO port in a device.
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FXS ports are always in connection with the FXO or Foreign eXchange Office ports that are the plugs on your devices. A PBX, or a Private Branch Exchange (server), can be installed between your FXO and FXS ports, and via Internet, it will be able to connect your analog phone system to a Voice over Internet Protocol (VoIP) server or to each other.

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