Worth Data 7100 RF Terminal Series Owner's Manual page 91

ISBN Specifications
ISBN (International Standard Book Numbering) bar codes are essentially EAN-13 with a 5 digit supplement, where the first 3 digits
are the Bookland country codes of 978 for books and 977 for periodicals. Although the bar code contains 18 characters, the ISBN
format uses only 9 of them, along with a newly calculated Mod-11 check digit. For example, a bar code containing the numbers
978055337062153495 would transmit as 0553370626 in the ISBN format.
The RF Terminal has the option of transmitting in the ISBN format.
ISBN specifications are available from:
American National Standards Institute
Customer Service
11 West 42
New York, NY 10036
http://web.ansi.org
document ISO 2108:1992
ISBN 0-553-37062
nd
St.
86