[GreenKeys] [External] Re: WTB J.H. Bunnell Pen Register Tape Reel / Arm

[Jones, Douglas W]

From: Jim Cooper [jim.w2jc at gmail.com]

> A picture or description of what they should look like, or what size and how

See the Wikipedia article  "pen register" 
-- https://en.wikipedia.org/wiki/Pen_register

(I had a hand in making the article actually look back at former uses of pen registers outside law enforcement, tracing the technology back to Samuel Morse and the terminology back to the 1890s, when pen registers were used to do what we now do with oscilloscopes.

        Doug Jones
        jones at cs.uiowa.edu