Two types each interrupts a different frequency band:
WARLOCK Green- Connects off of the 24V DC power supply of any military vehicle.
WARLOCK Red- Designed to connect off the cigarette lighter and/or 12V DC power supply.
Here is an explanation of the system from DefenseTech.Org:
“The Warlock radio frequency jammers are made by the New York and Simi Valley firm EDO. And they’re based on an earlier EDO product called the Shortstop Electronic Protection System, which is designed to protect troops against proximity-fused weapons like mortar rounds and artillery shells [by detonating them early]. The Warlock doesn’t do anything quite so dramatic. Instead, “it basically works by intercepting the signal sent from a remote location to the IED instructing it to detonate,” an Army official told Inside Defense (which has a wrap-up of all its recent IED stories here.) “The signal ‘cannot make contact, therefore when it can’t make contact it doesn’t detonate,’ much like a cellular phone call that does not connect, he added. “The cell phone never gets through, but [enemy forces] think it go through.”