[GreenKeys] Associated Press Special Dataspeed Receivers

[Jim Haynes]

On Fri, 9 Jan 2009, Don Robert House wrote:

> Six level advanced feed hole Type 2 Dataspeed receivers.
>
> I designed the circuit and station equipment for the last installation
> at Paddock Publications in Arlington Heights, IL in the 70's
> Clever subset allowed for switch settings depending on the type of
> news to be received.  I have always hoped that at least one would
> still be around.
>
> ...  USAF and the Atomic
> Energy Commission also used the BRPE AND GRPE.
> My favorite was the DRPE.  A really fast punch.  More than 1000 words
> a minute.

GRPE?  That's one I don't know.

The DRPE was in somewhat the same category as the Inktronic, a kluge
(too clever for its own good).  The idea was that the electromagnet
holds up a metal reed. Cutting off the current releases the reed,
which swings down, drives the punch pin through the tape, and swings
up and the magnet grabs it again.  One problem was that the reeds
need a lot of magnetism to pull them up when power is first applied
and they are in the neutral position far from the magnet pole pieces.
But it seems and looks like such a simple thing, just a magnet and
reed for each punch pin and the only motor is a little one used to
feed the tape.

The worst problem was eddy current generation in the solid metal reeds.
They would get red hot.  The solution was to grind out a depression
in the reed and fill it with a ceramic magnetic material.  At first
these inserts were glued in with epoxy, but the bond tended to fail,
so they had to be held in with pins.

Another problem was the acoustic noise level, much worse than any
previous product.  I remember when the punch was being developed in
the old Wrightwood building in 1959 - sounded like somebody was
running an (old model, poorly muffled) power lawnmower in the lab.
It took lots and lots of padding and muffling to get the thing to
be tolerable for use in an office.  The padding was probably that
same stuff that turns to crumbs when it ages.

There were three generations of drivers for the DRPE.  The first, used
only in a demonstration model, used conventional high voltage high
resistance, just like in a selector magnet loop, to get fast
response.  It was tremendously wasteful of power.  The second design
used some big inductors, and a scheme of shuttling energy between the
punch magnet and the inductor, for a considerable saving in energy.
This was used in the FAA Service B switching system, which I believe
was the first production use of the DRPE, and in the high speed ASR
set for Long Lines Project 176, another government system.  The third
design used a brief pulse of high voltage to pull the reed toward the
magnet and then a lower voltage to hold the reed attracted.  This was
used in Dataspeed Type 5, and later in Type 4.

Oh, yeah, the advanced feed holes of 6 level Teletypesetter operation.
What that means is, in 5 through 8 level paper tape the centers of the
small tape feed holes are on a line that passes through the centers
of the code holes.  But in 6 level Teletypesetter the front edges of
the feed holes are tangent to a line that is tangent to the front
edges of the code holes, so the feed holes are "advanced" in comparison
to the other way.  I have no idea how it got to be this way, but this
is the way it was.  So we had in mind a reader and punch with user-
adjustable tape guides to handle any tape width from 5 to 8 levels;
except it wouldn't work for 6 levels because of the requirement for
advanced feed holes.

The BRPE punch was popular in a lot of applications, such as computers,
to the extent they used paper tape at all.  Tally Register Co. was a
competitor of Teletype for this kind of product.