The ``phone phreak'' (phreak for short) is a specific breed of hacker. A phreak is someone who displays most of the characteristics of a hacker, but also has a specific interest in the phone system and the systems that support its operations. Additionally, most of the machines on the Internet, itself a piece of the Public Switched Network, are linked together through dedicated, commercial phone lines. A talented phreak is a threat to not only the phone system, but to the computer networks it supports.
There are two advantages of attacking systems through the phone system. The first advantage is that, phone system attack are hard to trace. It is possible to make connections through multiple switching units or to use unlisted or unused phone numbers to confound a tracing effort. Also by being in the phone system, it is sometimes possible to monitor the phone company to see if a trace is initiated.
The second advantage to using the phone system is that a sophisticated host machine is not needed to originate an attack nor is direct access to the network to which the target system is attached. A simple dumb terminal connected to a modem can be used to initiate an attack. Often, an attack consists of several hops, a procedure whereby one system is broken into and from that system another system is broken into, etc. This again makes tracing more difficult.