Line of Duty acronyms: your essential guide to all the police terms and jargon, including CHIS and OCG From DIR to TWOC, here's a handy guide to the workplace terminology flying around in season 6 of the police thriller 30 April 2021 • 4:33pm Adrian Dunbar says it's a badge of honour trying to learn the LoD lingo Credit: Steffan Hill Do you know your Reg-15 from your AC-12? Is there a UCO in the OCG? WTF is going on? Yes, some of the law-enforcement lingo in blockbuster BBC hit Line of Duty can be a little impenetrable to us civilians. That’s part of its appeal.