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. The module enables the TDM2400P to terminate four analog telephone lines per module. With Digium's Asterisk Open Source PBX software, you can build your dream telephony environment with all of the high-end features of a business telephone system.

Digium TDM2403B - 0 quad FXS, 3 quad FXO

Digium TDM2404B - 0 quad FXS, 4 quad FXO

Digium TDM2405B - 0 quad FXS, 5 quad FXO