TDoS - telephony denial of service

Emergency-service providers and other organizations are being targeted with TDoS (telephony denial of service) attacks, according to a security alert (PDF) from the Department of Homeland Security and the FBI, obtained by security expert Brian Krebs. TDoS attacks use high volumes of automated calls to tie up target phone systems, halting incoming and outgoing calls. Perpetrators are using the attacks to extort cash from target organizations, who receive a call from a representative from a purported payday loan company, who demands payment of $5,000 for an outstanding debt — usually speaking in an unspecified 'strong accent.'"

Fonte: Slashdot