The X100M FXO module allows 400 Series or 800 Series analog cards to terminate a single analog line per module.
Because of the modular design, you can activate additional ports at any time with more S110M or X100M daughter cards. The X100M module passes all the call features any standard analog telephone line will support.
FXO (Foreign Exchange Office)
FXO is an interface that connects to a trunk line, like the one from your service provider. It receives ringing voltage and battery from FXS devices. FXO interfaces are used to connect your PBX to the PSTN. One FXO channel is required for each line your receive from your telco.