Other schools claim to be scheduled if they require work to be completed within a certain time frame. Unscheduled courses are available at a website and can be accessed whenever the student has time available. Courses also differ depending upon the immediacy and amount of interaction that occurs. Synchronous courses use new technologies to provide real-time dialog, sometimes even visual exchanges. Currently few Web courses provide for much of this, though some few use it extensively.
Asynchronous courses allow for communication only through email or even snail mail.
We will use three terms to describe courses offered through virtual schools. Because of scheduling problems, especially across states and time zones, the largest category of courses are unscheduled, asynchronous courses. These may be taken at any time and do not provide for immediate exchange of ideas. Scheduled, asynchronous courses are offered at fixed times, but because of bandwidth problems do not permit immediate exchange of ideas. Fully synchronous courses are at a fixed time and provide for some immediate exchange among the teacher and members of the class.