The S400M FXO module allows you to connect an additional four (4) analog telephone connections to your existing TDM2400P, TDM800P or AEX800 board.

Because of the modular design, a user can activate additional ports at any time in groups of four, simply by adding more S400M or X400M daughter cards. The S400M module passes all the call features any standard analog telephone line will support.

You can also add the X400M FXS Module to connect more analog PSTN lines to your Digium analog card.