Maser
From Halopedia, the Halo wiki
Masers (Microwave Amplification by Simulated Emission of Radiation) are the primary method of communication on UNSC starships. Factually, they are devices which emit microwave radiation. They were first referred to in Halo: Contact Harvest, where the DCS cargo freighters, the Tiara and Mack's data center use the devices.
