Redfone Communications has a very interesting product coming to market - a solid state, virtual plug-and-play "appliance" used in conjunction with Asterisk which can be used instead of Digium or Sangoma cards. In addition, using the Redfone foneBRIDGE you can create a redundant deployment of Asterisk. As seen by the diagram below, you can configure multiple Asterisk servers - none of which have any TDM (PRI/T1) hardware cards in them. Instead, you use the foneBRIDGE to terminate to PRI or T1 channel banks on the trunk side and Ethernet to connect to the Asterisk boxes.


Basically, the foneBRIDGE is a plug and play box that gives you 4 T1s (Quad Span) instead of using Digium or Sangoma hardware in the Asterisk box. It connects to Asterisk over Ethernet employing native Asterisk TDMoE (TDM over Ethernet) format and utilities. I should point out that the foneBRIDGE doesn't require an A/C adaptor/brick since it uses Power over Ethernet (PoE) (Includes Single PoE Injector, 6' RJ45 Ethernet Patch Cable, and AC Power Cord).

Asterisk Redundancy Explained
If one Asterisk box goes down, you don't lose the Quad Span T1 trunk access, since the trunks are terminated via the foneBRIDGE appliance, which is a self-contained unit separate from the Asterisk hardware and software. I should point out that this is a much more cost economical redundant setup. If you were to do a redundant setup with Digium or Sangoma cards, with multiple Asterisk servers - you'd have to purchase one or more Quad span cards for each Asterisk box.

At $2495/ea it is about $1000 more expensive than a Digium TE405P, TE410P, or Sangoma A104. It is only slightly more expensive than new style Digium and Sangoma boards with echo cancellation. Redfone claims that the interface appliance helps out with the heavy lifting, and requires less CPU/System resources so the host servers don't have to work as hard.

The overall cost savings comes in ease of deployment, it takes about 5 minutes to implement, and you don't have to run Digium/Sangoma boards in your primary or failover Asterisk servers.