[GreenKeys] Bunnell Pen Register

[Harold Hallikainen]

Thanks for the info! I had heard that these were used for fire alarm
boxes. This one is from a local telephone company and is now at the
Telecom History Group in Denver where I am working on it. I suspect it was
used as a Dialed Number Recorder. That seems to have been a large
application of pen registers. A Google search on the term turns up lots of
court cases referring to pen registers and court authorizations to use
them to record dialed numbers.

The THG museum currently has a demonstration with a straight key and a
telegraph sounder. I'm thinking of adding the pen register to that. I
might also add a telephone dial so people can see what dial pulses look
like. If I can find a fire alarm box, I could maybe add that.

THANKS!


Harold

>  Harold -
> I can't comment on the specifics of this unit, but it might've been used
> to record digital alarm transmissions from a McCulloh system type alarm,
> which originated in the late 19th century.  I don't remember the pulse
> rate, but it was pretty fast - and variable.  They used a wheel with
> teeth in it that could be broken off to provide a unique code (like one
> bit of an answerback drum), and were driven by a wound spring clockwork
> mechanism, hence the speed variations.  In the early 90's, I did some
> consulting for an alarm central station that had dozens of these pen
> register devices in 19" racks, assigned to groups of customers.  The
> units dated from the 50's or early 60's, and served legacy customers. 
> The central station wanted to get rid of the pen registers (they were
> having trouble sourcing the paper tape - sound familiar?) and use a PC to
> decode the signals, and transmit them via RS-232 to other equipment that
> would display the information on an operator's console; the old way
> required the operator to note when a register would buzz and start
> spitting out tape, then walk over to it and decode the tape visually.  It
> was a bit of a challenge to accommodate the variety of speeds from
> different transmitters, and the speed variations depending on how much
> tension was left in the clockwork mechanism.  On top of that, everything
> in the system had to conform to UL central station requirements, which
> were pretty draconian...  
> Good luck with your unit.
> Keith
>     On Wednesday, January 29, 2020, 11:46:51 PM CST, Harold Hallikainen
> <harold at w6iwi.org> wrote:
>
>  Not quite Teletype, but it IS printing telegraph! I've been working on
> one
> of these pen registers.
>
> Nameplate:
> J. H. Bunnell & Co., Brooklyn New York
> Pen Register
> Model KS-3106
> Serial Number 1 1068
> Res 150
>
> A manual on the device is available at
> http://etler.com/docs/BSP/030/030-340-701_I2.pdf . This manual uses the
> pen register as a Dialed Number recorder. I believe they were originally
> Morse recorders and also fire alarm recorders.
>
>
> The unit seems to have a mechanical alignment issue that I have not been
> able to resolve. The shelf and feed wheel seem to be closer to the body of
> the unit than the printing wheel. Guides near the tape reel are one
> distance from the body, and guides near the feed wheel are closer. This
> results in the tape slowly working its way off the feed wheel as shown on
> the video at http://w6iwi.org/tmp/20200129_141035.mp4 .
> Note that I reused tape, so there are more marks than there should be on
> the tape.
>
> Does anyone have a suggestion on how to keep the tape from falling off the
> feed wheel?
>
> Also, the tape moves pretty fast for Morse use (probably good for dial
> pulses). Does anyone know where the tape speed adjustment is?
>
> Thanks!
>
> Harold
>
>
> --
> FCC Rules Updated Daily at http://www.hallikainen.com
> Not sent from an iPhone.
>
>
>
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