At this time there are no hotkeys available within the RealPresence Desktop application. If this is something that you would like to see added in the future I would suggest talking with your reseller/sales rep for a future enhancement.
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Polycom Global Services
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Please also make sure to check the below link for more RPM information http://support.polycom.com/PolycomService/support/us/support/video/realpresence_mobile/realpresence_mobile_overview.html