What is the difference between RJ11 and FXS ports?

 RJ11 is a physical connector commonly used for telephone wiring, featuring four or six pins. FXS (Foreign Exchange Subscriber) ports, on the other hand, are used on devices to provide analog telephone service, delivering dial tone, ringing voltage, and battery power to connected telephones. While RJ11 refers to the type of connector, FXS describes the functionality of the port in a telecommunication system.