Linking fields
Detailed information about the components of a linking entry field in CONSER records is found in the CONSER Cataloging Manual (CCM) 14.1.4.
...
The former practice of using 776 field subfield |c Original in records for microfilm reproductions has been discontinued under RDA. Subfield |c Original was used in place of subfields |a, |s, and |t for the catalog entry of the resource reproduced. Although this method is still described in the version of CCM Module 32 that is in Cataloger's Desktop as of 6/24/19, it is being discontinued. See the CONSER Program's web page for an early draft of the revised CCM 32.3, and the MARC documentation about subfield |c: 76x - 78x Linking Entry Fields.
Subfield |i
CONSER preference seems generally to use the natural language labels "Print version," "Online version," "CD-ROM version," "Microfilm version," etc., in such linking fields, when appropriate. The reason for this may be that these are considered easier for library users to understand. However, there are examples throughout CONSER documentation that instead use relationship designators. For instance, the examples in the draft newly revised CCM 32.3 show a preference for "Microfilm version," but CCM 32.3.3 states that either "Reproduction of (manifestation)" or "Print version" can be used to link from microform reproductions to print originals.
...
776 08 |i Print version, 1899-2016:
530 field: Additional physical form available note
CONSER catalogers generally only use a 530 note when there is no English-language-of-cataloging OCLC record to which to link and there is no ISSN. In other words, a 776 consisting only of the authorized access point plus the ISSN is preferred rather than a 530 note. Linking fields are preferred whenever possible because of the possible functionality of ISSNs in subfield |x, etc. Catalogers use text in subfield |i instead of a 530 note to record any complex details about a particular relationship. To avoid redundancy, generally 530 fields are not used when linking fields are employed to express the same relationship.
...