If I have 2 locations, one in US and one in China. Should I have 3CX server on each location? Please note the network latency between US and China is high at 170 ms. How SIP and VOIP work: let say my 3CX server stay in US, 2 of my remote users using softphone on their trip, one in HK, one in China. When HK call China using softphone, how the traffic going between them? Directly from HK to China or they have to route from HK back to US and to China? For 2 locations above, if I want to route call to China number from US to my location in China, what equipment should I have? Assuming I use analog lines in both locations. Do I need only FXO gateway? If I only have 1 3CX server in US location and buy one FXO gateway for each location. Can I configure 3CX server so that when I call US, use gateway 1, when I call China, use gateway 2? Thank you in advance.