The digital (electromagnetic) pen works slightly differently, instead operated by a signal that tells the interactive whiteboard the 'X, Y' coordinates of the pen and move the mouse accordingly.
This is the same system used by graphics tablets for digital design and allows for greater accuracy and less set up and won't become damaged by excessive force as might a touch based interactive whiteboard.
Multi-touch operation can be achieved by using more than one electromagnetic pen.
A third system has recently been developed that makes use of a Wii remote and the Nintendo Wii device combined with a projector and whiteboard to create a makeshift interactive whiteboard.
This significantly lowers costs but alsoreduces functionality and precision.
While this is an acceptable alternative for the classroom, it is less appropriate for office environments and will not come with the same software packages.
Interactive whiteboard installation varies from one installation to another by the type of projection used.