It looks like you already uploaded it to Manx: https://manx-docs.org/collections/antonio/dec/standards/el-00012-00-0000.pdf Looking though that led me to DEC STD 012-2 "Unified Numbering Code for Part Identifier Class Codes": https://manx-docs.org/collections/antonio/dec/standards/el-00012-02-0000.pdf which was exactly what I wanted. It's not the thing I remembered, but as DEC's official list, in some ways it's better (although it's so detailed it's kind of overkill :-)! Volume II had a brief but early 'class code' list; I made good use of it. Thanks everone! Much appreciated! Noel