្ដ from ដ(dɑɑ) (ដ្ដ) is homographic to ្ត from ត(tɑɑ) (ត្ត), and is the cause of a great many misspellings. Many Cambodians do not distinguish between the two subscripts, and type either of them for both subscript letters. They consider that a single glyph does duty for both letters.
This letter belongs to the Khmer a-series consonants