noun
native character set
Computing term for a character set that is built into a system or device, as opposed to one that is loaded externally.
このプリンタは固有文字集合しかサポートしていない。
This printer only supports its native character set.
Compound of 固有 (inherent) + 文字 (character) + 集合 (set). A straightforward technical term with no special historical derivation.