What does 2600 mean
2600Hz was a tone that was used by early phone phreaks (or phreakers) in the 80's, and some currently. If the tone was sent down the line at the proper time, one could get away with all sorts of fun stuff.
The 2600 hertz tone was simply the first step towards exploring the network. If you were successful at getting a toll call to drop, then billing would stop at that point but there would be billing for the number already dialed up until the point of seizure. 800 numbers and long distance information were both free in the past and records of who called what were either non-existent or very obscure with regards to these numbers. This, naturally, made them more popular than numbers that showed up on a bill, even if it was only for a minute. Today, many 800 numbers go overseas, which provides a quick and free way into another country's phone system which may be more open for exploration."