Voice over Internet Protocol (VoIP) allows voice communications to be transported digitally through a network using Internet Protocol standards. This NIJ In Short Fact Sheet gives an overview of the benefits and the challenges that VoIP presents to public safety agencies and emergency call takers. Chief among the challenges for public safety agencies is that traditional techniques for locating 911 calls and for telephone intercepts and wiretaps are incompatible with IP-based telephony. The fact sheet discusses plans to address these challenges by public safety organizations and Federal law enforcement and regulatory agencies.