telecommunications interface which allows data to be transferred between a personal computer and a desk top telephone and which allows the personal computer to control the operation of the desk top telephone; computer programs which integrate computers and telephones; computer programs for voice mail and message management; computer programs to enable data sharing; computer programs for video teleconferencing; microprocessors; computer circuit boards; apparatus for delivering multimedia video telecommunications; video teleconferencing terminals; switching and transmission apparatus for video teleconferencing