What goes around comes around

These are a couple of old circular bar codes, dating back to the 1970’s.

The first example was used to track totes filled with tape measures and divert them to the proper gate on a conveyor. The computer system that this symbol was used with was a Computer Identics laser scanner attached to a DEC PDP-8 with Plessey MOS memory and a ‘flip chip’ card decoder on a separate backplane. The scanning software loaded via a paper tape reader.

This is a binary encoded symbol with a value of ‘72’.  The laser scanner only read half of the label, and after it was decoded, the computer diverted the tote to the gate associated with the value 72. This was one of the oldest bar code systems that I have worked with.


The next example is called ‘Split Circle Code’. It was developed in  1974 by Bendix Recognition Systems.

The circle was split in half, with each half encoding part of the symbol.  This type of symbol required that both halves of the circle be read, so there were orientation issues that had to be dealt with in order to get good reads.

Bendix encoded these symbols as BCD (binary coded decimal) values and they were printed by Bendix printers.

This example was used in a baggage handling system at Eastern Airlines which used a Bendix scanner to read the labels at a rate of 70 bags per minute.

You can still see the texture of the luggage that the label was applied to.

Apparently, many customers had complaints about the adhesive residue left behind when the label was removed and this ultimately led to the demise of these scanning systems.