A priority A-1 channel was a secure communications channel used by the Federation to relay a priority 1 distress call, denoting a disaster, to Starfleet vessels.

In 2268, Federation Undersecretary of Agriculture Nilz Baris who was on Space Station K-7, ordered that a priority 1 distress call be sent out on the A-1 channel which was later intercepted by Lieutenant Uhura on the USS Enterprise. As it turned out, Baris had sent out the distress call on the A-1 channel merely so that quadrotriticale, the only grain that would grow on Sherman's Planet, would be guarded by Starfleet officers from being tampered with by the Klingons, who wanted to claim the planet for the Klingon Empire. (TOS: "The Trouble with Tribbles")