It is used to set up and clear calls for both of the information B-channels. The Magic of the D Channel. The key to this power is in the seemingly mundane D channel of an ISDN connection. Users can literally control the telephone network, using logical commands from a computer, a PC or an ISDN telephone. For example, they can have calls seamlessly forwarded to a car phone, a distant office, a home or almost any other location.
Users can also set up logical parameters for call forwarding.
Response can be based on the time of day, on who a call is from, or on data the caller enters in response to recorded prompts. Advanced call handling. The D channel also gives users extended control of a call. While transmission of this information is legally prohibited in some areas, it has proved of great benefit in a range of systems and applications where available.