[GreenKeys] DRPE Punch

[Jim Haynes]

There were (at least) three different drivers for the DRPE  The original
one was for the demo model only.  I believe it used the typical high
voltage high resistance to overcome the inductance, just like a selector
circuit.  At any rate it was hugely power consuming.

The next use of DRPE was in the FAA "BDIS" system - Service B.  Patent
3,191,101 issued in 1965 to Al Reszka.  This used inductors to store
energy that could be dumped into the DRPE magnets.  This may have been
likely was used in the Long Lines Project 176 set, a secret government
communication system.

The third use I'm aware of was in the Dataspeed product line, specifically
Type 5.  This was an all-electronic circuit that used high voltage to
start the reeds moving and a lower voltage to hold them against the
magnets.  The engineer was Eugene Sullivan but I haven't found any patent
related to it.  It was probably also used in Dataspeed Type 4, which was
a screwball error detection and correction system that would pull tape
backward through the punch and then punch rubouts over it when it received
a block that wouldn't pass the error check.

Type 5 Dataspeed was a fairly low-speed system, 750 wpm and probably very
few receivers were sold as the main application was data collection and
the receive modem probably went straight into a computer without involving
punched tape.

A problem that developed in high speed applications was that eddy currents
heated the solid steel reeds.  I was told that the solution was milled-out
slots in the reeds that were filled with something like ferrite.

I would put the DRPE in the same class as the Inktronic printer - clever
idea, but ultimately impractical.

 	---

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