Free Telephony Project
"The goal of this project is to provide free (as in speech) reference designs for embedded telephony. Both the hardware and software are open. You are free to copy, modify and re-use the hardware designs."
"David Rowe, the author has almost single-handedly designed an embedded computer using a blackfin processor combined with FXO/FXS (PSTN lines) chips to produce an extremely low-cost PBX running uclinux and asterisk. Recent posts indicate he's also close to producing a T1 interface as well. The amazing thing about this project is how open it all is. The circuit design, and layout for all of the boards are open. Also, he's committed to using only open-source software to do the design (and contributed a number of enhancements back to these projects, such as pcb [sourceforge.net]). Not to mention also developing the uclinux based distribution, astfin, as well as a number of custom modifications to asterisk itself to use some of the Blackfin's special DSP capabilities." (slashdot)