The bottom line is that passive scanning in systems can expose a lot of information about all aspects of the system in normal communications without intruding upon operations. Active scanning has the potential to discover more information, and when combined with passive scanning, it gives a more complete picture.
Brick sizes vary depending on the country, the manufacturer and the purpose for which they are intended. In the United States, standard modern bricks are usually about 8 Ã 4 Ã 2.25 inches (203 Ã 102 Ã 57 mm). modular bricks are 7 5/8 long x 3 5/8 thick x3 5/8 deep.
The measurements and dimensions correspond to brick manufactured primarily in the United. States to a typical module of 4 in. (102 mm). Brick manufactured for projects requiring metric dimensions typically. conform to a module of 100 mm (3.94 in.). Although the principles presented here are the same for either system, care should be used when using the conversions given here for metric modular units and construction.