Features - Callback Connection
The Callback Connection feature of USB Redirector allows USB clients to connect USB devices even when USB server is located behind router (NAT) in a LAN.
Differences between direct and callback connections
Normally, to connect a USB device, the client initiates a connection to USB server, like the picture below shows.
If the connection is successfully established you will see a list of USB devices available for connection. But if USB server is located behind NAT or router you can not connect to this USB server, because its IP address may not be available from Internet. Callback connection was invented to solve such issues. It works the other way round and allows USB server to initiate a connection to USB client, like on the picture below.
To make use of callback feature, you need to create a Callback Connection to USB Client on USB server. When connection is established, USB client will be able to see a list of available USB devices and connect them in the same way as with direct connection.