If you still have an interest in telephony you might want to look at http://www.rowetel.com/blog/ http://www.rowetel.com/blog/ and his work on the Mesh Potato h

If you still have an interest in telephony you might want to look at http://www.rowetel.com/blog/ http://www.rowetel.com/blog/ and his work on the Mesh Potato http://www.villagetelco.org/about/mesh-potato/ http://www.villagetelco.org/about/mesh-potato/. It's an open source hardware project to create an easily deployed developing world "village telephony" system. Some really good content.