http://www.derivation.com/products.html
We have already done work with them-
http://findarticles.com/p/articles/mi_m0EIN/is_2000_Sept_25/ai_65457252
http://www.chips.navy.mil/archives/06_jan/web_pages/ACOMMS.htm
In the above article please note that the pc104 provides "the brains" and interface with acoustic communications---
Also, keep in mind that the TPL group is working on a sub-miniature audio device that is based on acoustic communications. GL, ads