A customer of mine has a Isotec 228 and a T-1 with 8 analog lines and Internet being delivered. The carrier has provided an adtran unit for delivery, conversion and seperation. We have went through 6 adtran units, something keeps burning out FXS lines on the adtran. The vendor did not have a replacement line card so he flipped 2 card positions and the trouble followed the bad card burning out the next 4 IAD600 FXS ports.
Any solution, this continues to happen.

Most IADs don't deliver dial tone at the specifications that were established by the FCC. The FCC is more focused upon cell phones these days than what they should be doing.

I seriously doubt that the 228 is causing this problem. More than likely, the voltage or loop current throughput from the FXS ports of the IAD are not in line with the standards that the 228 was designed to operate over. I've encountered instances where the line voltage was in the 34 volt range on these units, which is clearly 14 volts below industry standard.

The fact that you've gone through so many units has nothing to do with the 228. The FXS ports are not configured properly (if they are even adjustable).

You can always consider using loop current attenuators that work well in addressing these issues. High loop current works in both directions and the weaker component loses. Since IADs' CO line ports are pretty tough, I'm assuming that they are winning against the Adtran.

I agree with Ed that the most likely scenario is something out of spec. Adtran makes quality stuff - so a misconfiguration would be high on my list.
Another solution would be to have carrier hand off to you as DSX1 - put a T1 card (that are inexpensive these days) in the PBX and be good to go.
Cheers!

was the card set for ground start?
that could have something to do with this.