Gmm-u5j is one of the newest members of the u5 series GPS module featuring "Anti-J.A.C.K", or Anti-Jamming Assessment Command Feedback system: a powerful, easy to use jamming-detect and notification system designed specifically for critical asset protection and security.

Anti-JACK™ is able to alert the security system embedded with Gmm-u5j GPS receiver on nearby GPS jammers through its customized NMEA protocol, or via direct voltage level with dedicated hardware pin out. System integrators can transmit the protocol to a cellular radio of his choice to remotely alert users, or have it connect to a physical alarm or siren that blast out loud when the system is tempered with.