The VPMADT032 is a 128ms per-channel echo cancellation module for use with Digium telephony interface cards.

The X400M FXO (Foreign Exchange Office) module allows the TDM2400P card to terminate four analog telephone lines (POTS) per module. Because of the modular design, a user can activate additional ports at any time with more S400M or X400M daughter cards. The X400M module passes all the call features any standard analog telephone line will support. Worldwide certifications are pending.

The X100M FXO (Foreign Exchange Office) module allows the TDM400P card to terminate analog "plain old" telephone systems' lines (POTS). Because of the modular design, a user can activate additional ports at any time with more FXS or FXO daughter cards. The FXO module passes all the call features any standard analog telephone line will support.