Users have control over some equipment and receive feedback from it. For example, a remote robot might allow the user to drive it around and see where it is going. If several people want to use the robot then they have to queue and take turns, just as in a real lab. The simplest way of queuing is to rely on social protocols. Another option is to use a queue at the server end that alerts users when it is their turn.
Some remote labs require re-initialising between users.
In our previous example of a robot picking up a block, the robot and the block must be returned to their starting position. Similarly, a remote electron microscope will need its slides changing for different samples. The World-Wide Web is the most appropriate interface to most remote equipment. The design of the interface within the web browser depends upon the application. Real-time applications are a little more complex.