How to configure cisco2851 call managers over internet

[nyein chan tun]

Dear all expert,

            In my  HQ network, I used cisco 2851 for voip phones and using E1 line for voice. For data I use cisco 1841 router .

Now we need to configure voip phone in other oversea branch , and would like to configure voip phone as a local phone of HQ. For basically network diagram, I upload it and please see in attach file .

              I don't know which device should be used in oversea branch site and how to configure. please advise me .

Thanks a lot.

[paolo bevilacqua]

First, you configure a good robust VPN.

Then you can have the remote phone as if it was local.