Digium

Digium Profile - Founded in 1999, Digium is the creator and primary developer of Asterisk®, the industry's first Open Source PBX. Digium is the original creator and primary developer of Asterisk, the industry's first open source PBX and Asterisk Business Edition, the professional-grade version of Asterisk. Used in combination with Digium's PCI telephony interface cards, Asterisk offers a strategic, highly cost-effective approach to voice and data transport over IP, TDM, switched and Ethernet architectures.

• The naming convention for the TDM Series bundles is as follows: TDM# X Y B
  "TDM4" denotes that the card is TDM400P, "X" denotes the number of FXS modules, "Y" denotes the number of FXO modules, and "B" indicates that this product is a bundle without Echo Cancellation. "E" indicates that this product is a bundle with Echo Cancellation or "P" denotes that the card is the base card without any Modules bundled.
• Example: TDM21B is a 2 FXS / 1 FXO card without Echo Cancellation. This is a card within the TDM400 Series, unlike all other models the 400 series does not add the 4 into the Bundled Part Name.
• Example: TDM2413E is a 4 FXS / 12 FXO card with Echo Cancellation. This is a card within the TDM2400 Series.