On Thu, 29 Apr 2004, Kannaiyan Natesan wrote: This is a FAQ. It is not SER specific, and affects all SIP proxies. The media path for calls does not pass through SER. SER is out of the loop once the call is setup. You should probably review the main SIP RFC to get a flavour for the design of SIP, and why this is the way it is. The typical solution for this a B2BUA (back to back user agent). You'll see this term mentioned in the SIP standards, and all over the web. The B2BUA sits between the two user agents. Now, I imagine you are trying to build a pre-paid long distance system? The Vocal (Vovida) system includes a B2BUA server which supposedly can support a pre-paid application. In addition, some members of this list have commercial B2BUA available for sale. I understand the Tangerine softswitch now includes a B2BUA with an ready to use pre-paid application. Tom