Description:

As we are preparing to provide training on v19 changes to functionality, we cannot get the Field Validity Check on ISSN or ISBN number to work correctly. This is how we have the 020 and 022 check_doc_line_contents defined:

! 2 3 4 5
!!-!!!!!-!-!!!!!!!!!!!!!!!!!!!!-!!!!!!!!!!!!!!!!!!!!
## 020## a isbn
## 020## a issn/isbn
## 022## a issn
## 022## a issn/isbn

When I add an ISBN to the 020 with a value of 1234567890 I get the error message:

ISBN "1234567890" is incorrect

When I add an ISSN to the 020 with a value of 0748-2560, I get the error message:

ISSN "0748-2560" is incorrect

Why is the system giving me these error messages? The ISBN has 10 digits and the ISSN has 8 digits with a hyphen in the middle.
 

Resolution:

The numbers really are incorrect. Both of the ISSN and ISBN have check digits (modulus 11). This is to help insure that there isn't a typo in the number being entered. The ISBN check digit (the digit in position 10) should be X, yielding 123456789X. The last digit of the ISSN should be 6, yielding 0748-2566.

The algorithms for calculating the check digits can be found at the following locations:

ISSN:
http://www.loc.gov/issn/check.html

ISBN:

See 'APPENDIX 1 Check digit calculation and distribution of ranges' in document 'ISBN user manual' at https://www.isbn-international.org 

• Article last edited: 16-June-2017