The Digium S400M FXS module enables the TDM2400P to terminate four analog telephones per module. A user can activate additional ports at any time with more S400M daughter cards.

The Digium X400M is a quad FXO interface module for the TDM2400P

Digium VPMADT032 Echo Cancellation Module for use with the Digium TDM800P and Digium TDM2400P

The Digium TDM800P is a half length PCIx 2.2 compliant, 4 port card that support 4 analog telephone lines.