The PDP-11/40 I used was at the local college and we had a TTY stuck in an old store cupboard at my school. This would have been about 1978. I was only 12, but as my mom was a teacher and good friends with the head of the math dept., I got access whenever I wanted.
It was a real luxury to go down to the college and use their Cifer VDT's. They also had a huge room with about 25 ASR33s, and boy was it noisy when they were all in use. But I digress again....
The acceptance of 4-wire deltas in the U.S. is fascinating. It would be interesting to know how widely such systems (and other "oddball" systems like corner-grounded delta) are used elsewhere, whether they were once used and discarded, and so on. Are they so prevalent in Canada, or other parts of the Americas which generally follow U.S. practice in other respects?
I'm assuming that 120/208 Y dates back to the very early days of 3-phase distribution. But if 240 delta, 480 delta, and the 4-w delta were once very common, when did the 277/480 Y system make it's debut? And why did Canada end up with 347/600 volts?
Sorry about all the questions folks, but I'd really like to get an idea of the historical development of all these systems.