This article is about reading and understanding typical ANSI X12 specifications, generated with tools like SpecBuilder in PDF or MS Word format. Usually specifications are straight-forward, but there are some nuances you should be aware of.
An X12 specification is a particular implementation of X12 transaction, defined by a company to be used with its partners.
Prerequisites: you should be familiar with X12 components, such as transactions, loops/groups, segments and elements.
1. Cover Page
Often (but not always) it starts with a Cover page which contains X12 transaction set number (such as 850 for Purchase Order or 810 for Invoice), version, publication date, author, logo and some other things.
The most important information is Transaction Set number (856 on the picture above) and X12 version (4010). Also I usually check the publication date to make sure it is not too old – if it is from 1990s, I would probably ask if it is the latest version.