Code 1-Alpha-Zero

From Memory Alpha, the free Star Trek reference

Code One Alpha Zero is a increased state of readiness aboard a starship in which the crew prepare for answering a starship distress call.

Commander Riker ordered a code One Alpha Zero - "Ship in distress" when it was learned that the USS Jenolan had crashed on the outer surface of the Dyson Sphere. (TNG: "Relics")