Click to Dial - Initiate phone calls by sending code to Asterisk PBX which sets up call from the assocaited extension

Click to Dial from Microsoft Office 365 applications. We need the application to initiate the call from a physical handset (we mostly use yealink and asterisk PBX) There was a program called TeleTrigger that had this functionality that is no longer available. At the moment the best solution seems to be SIPTAPI which is probably the best approach to use. I am not a expert in software design and open to suggestions, but feel the most open approach would be for the application to be built as a plug in that take the number from the contacts and embeds in code that registers with PBX as the extension (similar to what SIPTAPI does), and sends the codes to the PBX that sets up the calls. This way we do not need to support multiple handset vendors as the codes to setup these calls with Asterisk are fairly standard. Would like to start with plugin for outlook with the view to also building a plugin to work with Skype for Business and then a registration server and web shop to sell and manage the licences. Understandably costs will change as the project develops, but first stage is a functional Outlook plugin that does not rely on TAPI as I believe Microsoft are planning on stopping support for TAPI. An alternate approach could be to design a windows app that scans the active window for possible phone numbers (ie patterns that are definable by some wild card templates xx xxxx xxxx or xxxxxxxx etc) then when the mouse pointer is hovered over or right click on these patterns a click to dial icon is presented which takes this number pattern and sends to PBX to initiate call similar to what SIPTAPI does. This way the application could be used with any program and not limited to a outlook plugin.