The FAQ contains a post covering such functionality.
I am not near a PC and uaCSTA support on our phones is only very limited and old development and for more details your Polycom reseller and/or Polycom support should be consulted.
In addition UCS 4.1.0 for the SoundStation 650 is for LYNC support only so if you have a Sip server you should run the latest UCS 4.0.4 at present.
Notice: This community forum is not an official Poly support resource, thus responses from Poly employees, partners, and customers alike are best-effort in attempts to share learned knowledge. If you need immediate and/or official assistance please open a service ticket through your proper support channels. Please also ensure you always check the VoIP , Video Endpoint , Skype for Business , PSTN or RPM FAQ's