Hi there, i'm new to SIP, IP telephony. my organization abandond cisco infrastructure and moved to elastix 2.5. i have plenty of CP-7821 phones. but i cant figure out how to connect them to elastix server. here is what i have done so far: installed a virtual machine, elastix 2.5 and configured basic settings create a dhcp and applied the mac address of the phone created an extension the problem is that the phone is keep telling me (phone not registered). when i go to the network settings i find that it took an ip from the dhcp as i gave it, and tftp is the ip of my elastix server (so everything is yet good so far) i asked a friend and told me that i should put the 7821 SIP files in the tftp boot. i went to Cisco and downloaded the files, but they are different that the ones in tftpboot folder (no XML, no CNF, no anything), just SBN files and sip78xx.10-1-1-9.loads ... can anyone please give me detailed instruction on how to connect the 7821 cisco phones to elastix? i googled for two days with no specific instruction, and on YouTube they have video for older models and different methodologies. help ASAP please.