Last week I saw this article in EE Times on an open source hardware project called the Free Telephony Project. The project is providing a reference design and open source hardware for an Asterisk PBX based on the Analog Devices Blackfin embedded DSP. The device runs uClinux out of flash (no hard drives like a real telecom device.) One incarnation, known as the IP04 is being made available for purchase for about $450, but you can also download the designs and build it from scratch yourself. (When it's all said and done, you're probably better off buying one since it will pretty hard to compete with their volume pricing...)
Currently FXS (POTS station) and FXO (POTS central office) interfaces are available and T1/E1 ISDN-BRI interfaces are in the works. It would be nice if they could develop a 4-wire E&M interface which would be useful for two-way radio projects. One group of hams has already done some interesting linking work with Asterisk in a project called the Allstar Link Network. They are using app_rpt with the Zapata Telephony Quad Radio PCI Card. Thus, they've been able to build an IRLP or EchoLink-type network out of Asterisk boxes. I find this approach attractive because it's totally open. But while they seem to be off to a good start, by the look of their last updates things seem to be stagnating. Perhaps some cheaper hardware would reinvigorate things. If I only had more time on my hands....
