Chambers coil

From Memory Alpha, the free Star Trek reference

The chambers coil was a component found in a communications system.

In order for a communications system to get a stronger signal, the system needs to be switched to a higher-carrier frequency, which can be accomplished by resetting the actuators in the chambers coil. (DS9: "Armageddon Game")

During the USS Enterprise's initial contact with the USS Reliant, which was commandeered by Khan Noonien Singh, Lieutenant Uhura received a message stating that the Reliant's "chambers coil is overloading their comm system." However, when Spock scanned the Reliant, he discovered that their coil emissions were normal, indicating that the Enterprise was being deceived. (Star Trek II: The Wrath of Khan)