rently limited to operating systems and program language bindings. Protocols, on the other hand, have no such limitations. This is the single most important development enabling multiple vendors to create collaborative communications applications. Feature Activation Most business telephone systems provide over 100 fea- tures to improve call handling. The majority of users never use more than 4 of them! The use of computer-based applica- tions that can be set to the user's preferences unlocks the capabilities built into the telephone system. These applica- tions allow simple, screen-based control of features that are otherwise cumbersome to access. Using a mouse to point and click on your computer screen, you can activate and deactivate features in the telephone system. For example, a Personal Organizer application could set up call forwarding for a user who is away from the office and turn off that call forwarding when the user returns. In another example, a Computer Telephony application could modify call screening by a secretary on behalf of a group. The screening would be turned off at the end of the day and calls would be redirected to an answering service. Other Computer Telephony Applications Unified Messaging and Unified Communication Unified Messaging is an application that attempts to stream- line the work of receiving and responding to multiple messages from voice mail, e-mail and fax. It has been developed prima- rily by Voice Mail companies as an expansion of their system's capabilities. A user of unified messaging receives e-mail, voice 166 The Telecom Handbook CHAPTER 7 mail and fax messages all on the same software platform. All appear on the computer screen at the same time and can be scrolled through, responded to or deleted. The Voice Mail mes- sages are heard through the computer speaker and can be responded to through the computer if is equipped with a micro- phone. With Unified Messaging, laptop users can be listening to and responding to Voice Mail messages from anywhere, with- out being con