An object of the present invention is to provide a contact switching device having high dimension accuracy and an inexpensive price, and including a small sealed space. The writing board structure is defined by first and second injection molded plastic panels, each panel having a writing surface on one side thereof and a non-writing surface on an opposite side thereof. In a second embodiment the TAP and WSP based architectures are merged together such that the sharing of the previously described architectural elements are possible, and the TAP and WSP test interfaces are merged into a single optimized test interface that is operable to perform all operations of each separate test interface. During the phase change the temperature of the water will remain constant until all of the water has changed to gas.