Hi, I can develop the click-to-call plugins for both FF and Chrome. I worked on a similar plugin that allowed users to make calls to a YeaLink IP phone:
https://www.freelancer.com/projects/c-sharp-programming/Click-Call-plugin-for/reviews
I would like to know what kind of phone numbers you need to detect, international with country extension? local? and what type of phone communication you are using, over IP? or over the internet with a server?