Telenet and Tymnet were the main US X.25 networks. [1] X.25 was the global standard packet-switched network that preceded the Internet. It was mostly B2B, as it

Telenet and Tymnet were the main US X.25 networks. [1] X.25 was the global standard packet-switched network that preceded the Internet. It was mostly B2B, as it was pay-by-the-minute plus pay-by-the-packet, plus of course the cost of the modem phone call if any. Access to some of the X.25 networks was easily hacked, as there was almost no cybercrime back then outside of teenagers. In some cases, there was only a logon code - no password at all. I remember a network where the code was just a short-ish number, so it could be easily mined via brute-force search. The modem bank would disconnect you after X failed attempts, but you could just dial back in right away (there was no caller ID either.) X.25 had hosts called Outdials in most area codes that would let you make a local modem call back out for no extra charge, as long as it was toll-free. [2] This was a way to avoid expensive long-distance BBS calls, particularly if you were using a mined X.25 logon. The latency was pretty bad but the connection could be much more reliable than a modem on a noisy long-distance line. [1] https://en.wikipedia.org/wiki/X.25 https://en.wikipedia.org/wiki/X.25 [2] https://github.com/maestron/hacking-tutorials/blob/master/Basic%20Networking.txt https://github.com/maestron/hacking-tutorials/blob/master/Ba...