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From: wales@LOCUS.UCLA.EDU (Rich Wales)
Newsgroups: mod.telecom
Subject: (none)
Message-ID: <8612240416.AA04419@ucbvax.Berkeley.EDU>
Date: Tue, 16-Dec-86 20:08:46 EST
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Posted: Tue Dec 16 20:08:46 1986
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I have some observations and questions regarding the "bar codes" which
the U.S. Postal Service has been using for a while on mail.  These codes
are most often seen on preprinted reply envelopes and postcards (e.g.,
for paying bills, subscribing to magazines, etc.).  Every so often, they
get printed on private mail as well.

First of all, for anyone who may be interested, here's a description of
the code.  (I figured it out in my spare time last Saturday, by looking
carefully at several preprinted reply envelopes.)

(1) The code consists of a succession of long and short bars (about 3mm
    and 1mm high, respectively), spaced about 1.2mm apart.  The bottoms
    of the bars are lined up, which means that the long bars "stick up".

(2) The first and last bars are always "long" (presumably for alignment
    of the reading equipment).  The remaining bars are a representation
    of the ZIP code (either 5- or 9-digit version), plus a check digit.
    This means that the codes are either 32 bars long (for a 5-digit ZIP
    code) or 52 bars long (for a 9-digit ZIP+4 code).

(3) The digits are read from left to right.  Each digit is represented
    by five bars, using the following "two-out-of-five" code:

	    1 ...||    2 ..|.|    3 ..||.    4 .|..|    5 .|.|.
	    6 .||..    7 |...|    8 |..|.    9 |.|..    0 ||...

(4) A check digit is added after the ZIP code itself.  Its value is cho-
    sen such that the sum of all the digits in the code (including the
    check digit) will be a multiple of 10.  Note that the digits in the
    code are *not* weighted in any way when determining the check digit
    value -- it's just a straight addition.

(5) It appears that the bar code is supposed to be parallel to, and the
    tops of the "long" bars are supposed to be within about half an inch
    of, the bottom edge of the envelope or postcard.  I was unable to
    draw any more specific conclusions based on my observations.

Here's an example.  The ZIP+4 code on a reply postcard in one of my mag-
azines was 60604-9973.  Since these digits add up to 44, the check digit
is a 6.

	|.||..||....||..||....|..||.|..|.|..|...|..||..||..|
	   6    0    6    0    4    9    9    7    3    6

Now, my questions.

(1) Where do I find the document (for I'm sure there is one!) describing
    the exact specifications of this code?  In particular, something
    that indicates the tolerances for the various measurements, how far
    from the bottom edge the code can be, etc.?

(2) What are the regulations outlining the circumstances under which the
    bar codes will be, can be, or must be put on mail?

    (a) I'm sure all those businesses haven't put those codes on their
	reply envelopes out of the goodness of their hearts.  And, in
	the case of bill envelopes, I can't even see how the companies
	might be benefitting from a reduction in postage -- since the
	bill-paying consumer still has to put a stamp on the envelope!

    (b) Reasonably often (but not always), I see a bar code on a private
	letter -- apparently put there by a dot-matrix printer.  I would
	assume the Postal Service did this -- but why do they do it only
	on some envelopes and not on others?

    (c) With the increasing use of personal computers, it would seem to
	be an easy matter to write a program so that individuals could
	print these bar codes on their own outgoing mail.  Even if this
	didn't earn one a reduction in postage :-}, still it might help
	speed up mail delivery.  Has the Postal Service thought of this?

-- Rich Wales // UCLA Computer Science Department // +1 213-825-5683
	3531 Boelter Hall // Los Angeles, California 90024 // USA
	wales@LOCUS.UCLA.EDU   ...!(ucbvax,sdcrdcf,ihnp4)!ucla-cs!wales
"Sir, there is a multilegged creature crawling on your shoulder."