But doing good deeds for society wasn’t going to earn me any Brownie points with law enforcement. I figured out how to set up an early-warning system to sound an alarm if the Feds were hanging around waiting to follow me when I left work. I bought a RadioShack scanner that had the cellular band unblocked (the FCC had started cracking down on scanner manufacturers to prevent the interception of cell phone traffic). I also bought a device called a "digital-data interpreter," or DDI—a special box that could decode the signaling information on the cellular network. The scanner signals fed into the DDI, which was connected to my computer.