The question in the subject
Yes, you can retrieve this field using AdxRtList object of AdfinX Real-Time library (aka RTX).
I'm wondering why this field is a part of real-time data, but not fundamental in dex2
Historical reasons. This field has been part of real-time data record for decades since before fundamental & reference dataset even existed within what was Reuters then. Today you can also retrieve data contained in OFFCL_CODE field from fundamental & reference dataset using DEX2 library and fields TR.CUSIP, TR.ISIN etc.
I couldn't get OFFCL_CODE from dex2.
Do you mean TR.CUSIP has the same data as OFFCL_CODE?
OFFCL_CODE cannot be retrieved using DEX2. The content of OFFCL_CODE varies by RIC, but most commonly this field contains CUSIP or ISIN, or SEDOL, or another security identifier. These security identifiers can also be retrieved using DEX2 and fields TR.CUSIP, TR.ISIN, TR.SEDOL etc.
