The transport scrambler (also called a pattern scrambler) is a device designed to discourage transporter use in a certain area by disrupting the rematerialization process, destroying the subject being transported.
In the Second Federation-Klingon War, the Klingons used transport scramblers in ground battles to prevent the enemy from deploying troops effectively. (DS9: "...Nor the Battle to the Strong")
The Cardassians routinely booby-trapped their abandoned facilities with transport scramblers rigged to activate if they detect a non-Cardassian transporter signal. (DS9: "Empok Nor")
- See also: Remat detonator