Communicator Call от Bicom Systems

Communicator is a GLOBAL COMMUNICATOR desktop and mobile application designed to
enhance the communicating capabilities of enterprise and call center staff.
Appropriately termed "the future of communication", Communicator can be used as a
softphone or integrated with your IP phone to simplify and streamline
communications for individual workers and entire enterprises. Features
include: incoming and outgoing calls, video calls, instant messaging,
conferencing, group chat, fax, call monitoring, and much more.

This extension allows Communicator users to click-to-dial telephone numbers within
Mozilla Firefox.