"Don't know the trade ." A Street expression used whenever one party lacks knowledge of a trade or receives conflicting instructions from the other party.
DON'T KNOW (DK¸ DKED)
Meaning of DON'T KNOW (DK¸ DKED) in English
Campbell R. Harvey. Hypertextual finance English glossary. Английский словарь гипертекстовых финансов. 2012