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From: taylor@math.vt.edu (Frank Seaton Taylor)
Newsgroups: alt.snail-mail
Subject: Zip+4(+2 sortof)
Message-ID: <25sslh$e3n@vtserf.cc.vt.edu>
Date: 30 Aug 93 12:43:29 GMT
Organization: Virginia Tech, Blacksburg, Virginia
Lines: 18
NNTP-Posting-Host: legendre.math.vt.edu


The bar code (called the PostNet code) that usually appears above or
below the printed address has three formats now:

  1) Five digit zip code
  2) Five digit zip code plus four digit extension
  3) Five digit zip code plus four digit extension plus the last two 
     digits from your street address.

Although the extra two digits do not appear in your printed zip-code.
The newer OCR machines print them in the PostNet code that is generated
for PostNetted mail. Plus a small discount is given to businesses that
pre-print them. 

This should be enough information to identify a street address uniquely.
However it will not handle apartments within one building. And surely,
there are other circumstances where it will not work. (21 1/2 Maple St.
vs. 21 Maple St.---Now that I think about it.)


