III. The Technical Aspects That Allowed Phreaking To Work

VI. What's Left For The Phreaking Community

VII. Bibliography.I. Introduction - The '60s and '70s

It's hard for one not to be familiar with the state of our nation in the '60s and'70s. The period was arguably the high point of independent thought for the century. Average, everyday people began to question and disagree with aspects of society that had formerly been respected and revered. The new line of thinking greatly influenced the way society would advanced through that period.

The period in question was marked by a particularly hostile attitude towards those who were in positions of authority. The public was unhappy with the events surrounding the Vietnam War. For the first time, there was a large number of people who felt the need to speak up for what they believed in, even if it was against the government. The nation began to see the laying of foundations towards equal civil rights and disarmamen

Change tends to be popular for the younger generations. Older people are more set in their ways. Some would say that the generation gap is the chasm between differing points of view. The older generations of the '60s and '70s grew up with the idea that the government acted only in the best interests of the people, and that one should support the government in all ways possible. However, the inquisitive nature of the younger generation naturally caused them to tack the more defiant path. So, it is not hard to imagine that the new line of thinking that developed during this period bloomed from mediums related to the younger generations. For instance, pop culture contributed to this new way of thinking. If any one area contributed most to the new way of thinking, it would surely be the areas of higher education. College campuses allowed the younger people to come together and discuss current events, voice their opinions, and find like-minded individuals to associate with. Before long, the greatest areas of protest were college campuses. Thus, collegiate level educational centers became the homes of new independent thought

At this point in time, the Public Switched Telephone Network (PSTN) was a primarily (if not completely) analog network. It was designed to handle analog voice signals. Likewise, it used analog signaling to inform CO equipment of various line states. IT is important to mention that this signaling scheme was in-band. In-band means that the signals were sent over the normal telephone line, right along with the voice signals, and staying within the bandwidth of the line. Sometimes, while placing a call, one would actually be able to hear the office switches signaling each other, especially during a long distance phone call. This is due to the relationship between local offices (class 5 switching systems) and toll offices (class 4 switching systems), in respect to the trunk lines they share. These lines were loop start lines. This means that an off hook signal was given to the line if the loop (or circuit) was completed. If the loop was open, the line was not in use. Buy picking up the phone and dialing out, the customer caused the local office to complete a loop with the class 4 toll office. However, the lines between each class 4 office and other hierarchical offices dealt with Multi-Frequency (MF) signaling. On these trunk lines, there was a 2600Hz signal ever present, to signify the trunk was idle (not being used). If the class 4 toll office needed to route a call, it would cease sending 2600 across that line, to tell the other switch to wait for further instructions. Then the switch would send a combination of MF signals to signify the start of a number (Key Pulse, or KP), then the actual number in dial (consisting of unique MF signals to represent the digits 0-9), followed by the signal to signify the end of the number (ST). Now, assume for example that you are calling an 800 number. 1-800-555-1212, for example. You pick up the phone and dial. When you dial the first digit, 1, the local office switch realizes that you're going to need a long distance line. It send your request onward to a class 4 toll office switch. All this time, you're connected by loop start signaling. The signal won't be broken until you physically hang up the receiver. Now, the toll center switch gets a request to route the number 800/5551212, a number in the 800 Number Plan Area (NPA). The switch knows that this call is not a chargeable call, because the 800 NPA is a free call, from anywhere in the country. The toll office switch will send out the following MF string: KP8005551212ST. The proper switch will receive the request and the call will be connected. Now, here is what made phreaking so popular. If you blow a 2600Hz signal into the receiver of the handset, the furthest toll office (the one serving your number) and every other switch that you're using between the furthest and the nearest to

Some common words found in the essay are:
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Approximate Word count = 2831
Approximate Pages = 11 (250 words per page double spaced)