[GreenKeys] MYSTERY MACHINE

[jhhaynes at earthlink.net]

You might look for some additional nameplates.  LRXB  basically means
Model 28 reperforator transmitter base, to which some kind of
reperforator and tape transmitter are to be mounted.

These units were used for in-transit storage in switching systems.
Typically there would be two of them side by side in a cabinet,
and pull out on slides to replace the tape or do maintenance.
They might also serve as speed converters.  Typically the reperforator
is either typing or nontyping, which is pretty obvious from the
presence or absence of a type cylinder above the tape path.  The
tape reader might be plain (LXD)  or pivoted-head that can read right
up to the last character punched (LAXD) or fixed head dual-shaft
(LBXD).  The dual shafts in these units allow the tape reader to
run independently of the transmitting distributor.  There were also
some high speed to low speed converters and vice versa - things such
as a BRPE or DRPE high speed punch with an LBXD reader, or low
speed reperforator with a high speed (BX or CX) reader.  And some have
the LARP reperforator, which is a multi-magnet unit that will punch at
200 wpm.  Some of the bases have gear shifts - these were used when the
switching system served lines of different speeds and they wanted to
have a single spare unit that could work at any of the speeds.  Usually
there is also a container for the loop of tape between the punch and
the reader.

As a matter of interest there was a Model 14 line forerunner of this
kind of machine, called the FRXD, which combined a Model 14 typing
reperforator with a crawling-head dual shaft tape reader.  These
have a squarish base, and the tape reels are separate.  Then there was
the LRXD, a Model 28 item intended as a plug-compatible replacement
for the FRXD.

Jim W6JVE


jhhaynes at earthlink dot net