After the Update of the PioneerAVR Binding now supporting multizone, the documentation is not up-to-date anymore.
Here you can see an example for the item definition
/* Pioneer AVR Items */
Switch vsx529PowerSwitch "Power" (All) { channel="pioneeravr:ipAvrUnsupported:vsx529:zone1#power" }
Switch vsx529MuteSwitch "Mute" <none> (All) { channel="pioneeravr:ipAvrUnsupported:vsx529:zone1#mute" }
Dimmer vsx529VolumeDimmer "Volume [%.1f] %" <none> (All) { channel="pioneeravr:ipAvrUnsupported:vsx529:zone1#volumeDimmer" }
Number vsx529VolumeNumber "Volume [%.1f] dB" <none> (All) { channel="pioneeravr:ipAvrUnsupported:vsx529:zone1#volumeDb" }
String vsx529InputSourceSet "Input" <none> (All) { channel="pioneeravr:ipAvrUnsupported:vsx529:zone1#setInputSource" }
String vsx529InformationDisplay "Information [%s]" <none> (All) { channel="pioneeravr:ipAvrUnsupported:vsx529f:displayInformation#displayInformation" }
Dimmer vsx529Volume "Volume" <sun> (All) { channel="pioneeravr:ipAvrUnsupported:vsx529:zone1#volumeDimmer"}
The thing defintition has to look like
pioneeravr:ipAvrUnsupported:vsx529 [ address="192.168.0.10"]
Adding a port see:
https://community.openhab.org/t/pioneer-binding-configuration/11264