Diplomatic frequency
A diplomatic frequency was a frequency in the subspace bandwidth, reserved for diplomatic communications.

The Vulcans used a diplomatic frequency that was located in the lower band in the 22nd century. While chased by hostile Mazarite ships, Ambassador V'Lar used this frequency on board of the  to send the combat cruiser Sh'Raan "a message" in 2152. The frequency, unbeknown to the Mazarites, got through their jamming signal. ()
Communications technology