[GreenKeys] Fw: BBC enquiry - telegraph machine

[Don Robert House]

In the Bell System we called them "Pen Recorders"  They were used with  
old alarm circuits for fire and police.
We also used pen recorders, and the newer equivalent made by Gould, to  
track voltages and troubleshoot dial pulse problems.

Don
K9TTY
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On 17 Jun 2014, at 11:10 AM, Jim Haynes wrote:

An undulator is an ink recorder.  Like a slow oscillograph, the inked  
line displays on a moving paper tape the polarity and amplitude of the  
signal coming out of an ocean cable.  In ocean cable work they used  
one polarity
for dot and the other for dash, thus gaining speed.  And they tended to
push the speed of signaling above the bandwidth of the cable, so that
the operator had to infer what was sent from the wiggles on the tape.

Ink recorders were also used in high-speed Morse work (up to 500 wpm
on radio circuits) but I don't think those were called undulators.  And
they used conventional Morse make-and-break keying so the dashes were
3 times as long as the dots.

jhhaynes at earthlink dot net
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