I recently had the pleasure of installing this little beauty. The Sangoma A200 is a direct competitor (and threat) to the Digium TDM400P and TDM2400P. The most appealing part about the Sangoma was 100% compatibility with PCI 3.3/5v and generally quirky motherboards. The one size fits all approach is nice, as well. If you want to start small with 2 or 4 FXS/FXO modules and upgrade to more later, you aren't locked into a card that only supports 4 modules like the 400P.

A single A200 will support from 2 to 4 FXO/FXS modules, though is fully expandable up to 24. Using Sangoma's WANPIPE and Digium's Zaptel modules, this card appears to Asterisk as a standard Zap device, behaving exactly like a Digium analog product.

Though the Sangoma is easily 25% more expensive than the Digium cards, they're well worth it. They seem to work in just about any machine I've tried it in, including some very old Pentium II's -- which are not PCI 2.2 compliant.

The Sangoma also offers a version of the A200 with inboard echo cancelation. Though I have not personally tried this card, I'm sure it won't disappoint. They even responded to an e-mail support question on a holiday.

Nothing is perfect. Sangoma's documentation is poor, to say the least. Their driver support is still "beta", but seems to work great.

If you're looking for an alternative to Digium, look no further. :)