I'm hoping to be able to run 3CX off of XP Home / Pro or Vista Premium / Business and avoid the extra cost of a server license. My understanding is that Microsoft limits the desktop OS's to 10 concurrent TCP connections for security reasons. Has anyone had any problems with a fair sized number of extensions? Say up to around 50? As SIP communicates MOSTLY using UDP rather than TCP, I wouldn't THINK the 10 TCP connection limit in XP would apply, but I'd prefer to not find out after the fact Z.