Files with rca file extension is mainly related to a digital recorder format. Seems like obsolete format.
RCA file extension - RCA digital recorder format
What is rca file? How to open rca files?
File type specification:
The rca file extension is associated with the RCA/Lyra digital recorder and portable audio player.
The rca file stores recorded audio in digital file format. RCA/Lyra is obsolete product and RCA digital audio is not longer supported.
This rca file type entry was marked as obsolete and no longer supported file format.
This type of file is no longer actively used and is most likely obsolete. This is typically the case for system files in old operating systems, file types from long discontinued software, or previous versions of certain file types (like documents, projects etc.) that were replaced in higher versions of their original programs.