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SIP connection is established/closed when Connect/Disconnect button is clicked.
Call is placed/terminated when Call/Hangup button is clicked, and put on hold/retrieve when Hold/Unhold button is clicked.
Analyzing the code of the example
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SIP connection is established/closed when Connect/Disconnect button is clicked.
Call is placed/terminated when Call/Hangup button is clicked, and put on hold/retrieve when Hold/Unhold button is clicked.
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