DOC,
There's been some discussion in the Usenet newsgroups on this product - not all of it complimentary. As I recall there are/were two similar devices for general aviation on the market, and I think the term TPAS refers to a specific one.
Anyway, follow this link for a chronological listing of posts on TPAS:
<a href="http://groups.google.com/groups?q=TPAS&hl=en&scoring=d" target="_blank">http://groups.google.com/groups?q=TPAS&hl=en&scoring=d</a>