A short-pulse transmitter is a communication device standard in Colonial Vipers, capable of transmitting in scrambled code.
Captain Apollo asks Lieutenant Boomer to radio Galactica on the short-pulse transmitter after discovering Robber, Slayer and Tanya on an abandoned settlement, in the hopes of informing Galactica that Starbuck is alive and that there are no Cylons (TOS: deleted scene, "The Long Patrol").