I don't think I was clear. What I meant was How to set a callback("server to client") in a different connection from a "client to server" connection using WCF ?
I always saw callbacks examples using just one DuplexChannelFactory. This implies using only one TCP connection to make client to server calls and receive server to client callbacks.
This question came to me after I read this this topic: Seeking WCF Duplex "TwoWay" Subscribe+Callback Example
I the top answer, Ian Ringrose said:
Some rules I found to help avoid deadlocks. (Look at my WCF questions to see the pain I had!)
The sever must never call out to a client on the same connection as a call from the same client is in process on.
And/or
The client must never call back to the server on the same connection as is used for the “callbacks” while processing a call-back.
And I was wondering how to implement it using WCF.