2 ms·

I think these are the papers that lead to the blue box: http://www.alcatel-lucent.com/bstj/vol33-1954/articles/bstj33-6-1309.pdf http://www.alcatel-lucent.com/b

• th0ma5 16y ago
  It is weird that it hints at good vs. bad in inband vs. out of band signaling, but it doesn't talk about security, it is mostly concerned with maintaining good speech quality, and what kinds of tones are appropriate given the other line conditions...