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Actually it also can be registered to handle standard "callto://<number>" and "tel://number". If it doesn't work by default it can be turned on via "Settings | General | Set as default call and fax application". But it doesn't work with Chrome as far as I can see.

RingCentral supports URLs to activate Softphone and make a call. I.e., if a Softphone is installed on you local machine (Windows or Mac), you can type in a browser "rcmobile://call?number=<number to call>". And it will launch RingCentral for desktop.  

The RingCentral Connect Platform API is modern in the sense it is RESTful, implements OAuth2, and supports JSON. This enables any application capable of sending HTTP Requests and receiving/processing HTTP Responses can integrate with the RingCentral Connect Platform API.

Unlike *nix-based systems which typically have tools like cURL or wget available, DOS does not have these functionalities by default.

A quick Google for "Windows DOS HTTP Requests" returned this item on StackOverflow which looks promising (depending upon your development requirements): http://serverfault.com/questions/483754/is-there-a-built-in-command-line-tool-under-windows-like-wge...

Of course if a solution like that does not fit your requirements, you could also consider installing Node.js on the machine and then use DOS to execute those specific Node.js executables to achieve the same result. Following this approach requires having JavaScript experience (I would recommend this using the RingCentral JS SDK to simplify development). https://github.com/ringcentral/ringcentral-js.git