The connection method is determined by where the 3CX is hosted.

• CXD connection (RECOMMENDED) - when the 3CX is self-managed i.e. Hosted in your private cloud or on your internal network.
  
• Active connection - when the 3CX is self-managed i.e. Hosted in your private cloud: Amazon, Google, Azure, or on your internal network.
• Listening connection - for 3CX Hosted cloud systems.
  
  

Configuration details for all methods are shown below: