Dear, I am new to VOIP and I have some question regarding this matter. I want to build my own VOIP system and IP-PBX, and my question as follows: I've read here alot that you are talking about asterisk, what is the def. between Elastix and Asterisk. Is the Asterisk the same as http://www.asterisk.org or it is another thing? Regarding the hardware requirment, I've found some hardware like X800P-26 http://cgi.ebay.com/Asterisk-card-X800P ... 255c0b218f This one will give me the ability to connect two external Line and 6 Internal analoug extension, and I can connect unlimited number of IP telephone using normal switch, Do I have the correct understanding? Do I need to buy a device that has echo cancellation with it or it will be enough to buy normal one? I need to have an appliaction that can be installed in mobile phone "nokia, Iphone" so that I can connect to that VOIP system, what is the best one?