Asterisk is a software that turns a computer into a complete communications solution. With Asterisk we can develope an Asterisk PBX, a voice converter VoIP, Call Centers, voicemail, fax, and virtually anything you can imagine related to telephony. Asterisk is an open source project sponsored by Digium.
GRN uses Asterisk for all the voice solutions we offer. We assenble this software in a Supermicro server (or similar) with Digium, OpenVox or Bernonet telephony boards and SNOM or Cisco phones.