A Stonewall Jammer is a specialized piece of equipment only available to Advanced Tactical Response units. It is a type of signal jamming device that blocks crimes from being reported to a system's local security forces. Upon deployment to the site of a notorious criminal who has already murdered standard security forces, ATR ships activate Stonewall Jammers to place the site under lockdown and prevent additional standard security forces from being summoned while they subdue the criminal.
Stonewall Jammer activated. Attention all vessels. This area is now under lockdown. Make no attempt to deploy hardpoints.
— ATR comms message