[GreenKeys] Fw: BBC enquiry - telegraph machine

[Jim Haynes]

Let's keep in mind that there are two different flavors of paper tape
code recorders.  The one used for Morse Code at ordinary speeds, and
for recording telephone numbers and fire alarms, and often made by
J. H. Bunnell, uses an electromagnet to make an ink mark on the tape.
Or to emboss the tape.  The other kind, the undulator, is an analog
recorder, that records the magnitude and direction of current, not
simply whether the current is on or off.  That's what was used with
ocean cable telegraphy.

jhhaynes at earthlink dot net