Hello Sir,
Thank you for replying. So in my case it was like "PrepareForConnection". If so, is it that I have to initially invoke "PrepareForConnection" to get the "InstanceID" as output result and after that invoke action for Mute or volume UP?
I suggest you go to http://openconnectivity.org/upnp/specifications and download the bundle zip file: the contents should contain some kind of answers to a lot of questions like this (the interesting bits are in the UPnP architecture spec, UPnP AV architecture spec and the AV service specs. The last two are in "/standardizeddcps/MediaServer_4 and MediaRenderer_3/" directory).
I think the answer to the specific question is that you should use PrepareForConnection() when it exists but should not rely on the device implementing it. In practice using "0" as InstanceID seems to work everywhere.
