"SS7 is the protocol stack that governs call signaling and billing on the public switched telephone network (PSTN). SS7 is used by carriers as a common language for communicating call-routes and bandwidth consumption in the never-sleeping international telephone network...
"And an army of willing accomplices are already laying the groundwork, developing tomorrow's telephony systems. One of them is Digium, which makes hardware and software that lets you turn your Linux PC into a fully-functional soft-based voice switching system--like that elaborate, fridge-sized PBX at the office, only much smaller and cheaper. Digium's softPBX, which is open-source, is called Asterisk..."
