If you use Skype for Business, apparently it is not possible to have a conference call and include regular Skype callers. I would like to be able to include both Skype for Business and regular Skype callers on a call. Can I do this with regular Skype, so I'd initiate the call in regular Skype and add Skype for Business callers?
Skype Conference Call – How to Combine Regular and Business Callers
skypeskype-for-business
Best Answer
You can do the opposite: Use Skype for Business [=SfB] and (if not disabled by the SfB Administrator) your remote users invited could join as guests here with the Skype for Business Webclient which is asked to be downloaded during the join process.