have a way to send to Polycom hardphone (URI or something else) to cause it start Dial to given number? (directly not by originate)
You need to look for a ‘hotline’ option in the phone itself.
Depending on the handset you may find that this will give you an idea of whats possible. polycom.com/common/documents … _guide.pdf
look at third party call control. Not done this for Polycom but have done it for snom and Mitel using uris