greenphosphor

26_0020429 Rohr Collection Image

from SDASM Archives

• Chuck Walla said:

  I can't find any name for this Toshiba key system but the phones were white and used modular G-type handsets. They had electronic ringers.
  
  In the foreground is a historic artifact: a telephone message book. The book uses advanced technology known as "NCR paper." It replaced carbon paper. When the mmessage-taker wrote in this book, the pen pressure made a duplicate copy on a second sheet of paper. The paper was perforated so the message could be put into a mail box or handed to the target. The duplicate served as a log book.
  
  Computer display cathode ray tubles often had green or amber phosphor. Some human interface studies suggested these were the best for human readability. Search for NASA research if you're interested. Most IBM display I saw were green.