Back in the early 90's (possibly late 80's), I noticed a weird property of the
busy signal in my area. The effect I'm about to describe took place in the 437, 442, 443, 447, and 448 exchanges of the 203
area code (before these exchanges were separated from the 203
area code to form the 860
area code), possibly many more.
I was repeatedly calling a line that was in use (desperately trying to get a hold of a girl who had just broken up with me, if memory serves), and after a while, I just lied in bed and listened to the busy signal for a great while. Back then on that exchange, the busy signal wouldn't "time out" the way they do now that we're part of the 860 area code. After a good 10-25 minutes of busy signal, I heard a voice say
"Hello?"
"Hello." I replied, confused but playing it Bogart. The busy signal was still playing in the background, but a man's voice was clearly audible.
"Who is this?" Now, at this point, I mentally took a crack at what was going on. If you listen to the busy signal long enough, you'll be randomly connected to someone else listening to the busy signal, perhaps people whose phones are branched off the same trunk line.
"iiiiIIIiii aaaaMMMM tthheee maaasssterrrr offff the buuussssssyyyy siiigggnnnaallll...bow to me!!"
I could quietly hear "that's f*cked up" and a click, as the person on the "other side of the busy signal" hung up in confusion.
Around that same time, it was possible in the previously mentioned exchanges to successfully dial your own number and cause it to ring. My phone number was on the 447 exchange (meaning it fit the form 447-XXXX). I don't remember how I figured this out, but if I dialed 992-XXXX (where XXX are the last four digits of my phone number) and hung up right away, the phone would start ringing, with no one on the other end of the line. I would do this to use the telephones in the house as a free intercom, in case i was too lazy to shout across the house to get someone's attention. As with the busy signal trick, this stopped working when my local exchanges became part of the 860 area code instead of 203.
I've always wondered how and why this happened. Any writeups with further information on this would be greatly appreciated.