"Mister Spock, sometimes I think if I hear that word "frequency" once more, I'll cry."
"I was just trying to start a conversation."
"Well, since it is illogical for a communications officer to resent the word "frequency," I have no answer."
"No, you have an answer. I'm an illogical woman who's beginning to feel too much a part of that communications console."
There were many subspace frequencies over which hails were sent. Most of the major powers, such as the United Federation of Planets and the Dominion, had their own frequencies and protocols for sending messages such as distress calls, but there were also general frequencies. (DS9: "Waltz")
Jamming of hailing frequencies was a common technique used for purposes such as disrupting enemy communication in battle and preventing vessels from emitting a distress call. Most jamming techniques did not prevent the jamming party from sending out its own hails. Of particular note was the Breen method of sending out a rotating electromagnetic pulse. (DS9: "Sacrifice of Angels")
List of frequencies
- Subspace frequency 3 (TOS: "Operation -- Annihilate!")
- 384.2 gigahertz (ENT: "Fortunate Son")
- Comm frequency epsilon-2 (VOY: "Scientific Method")
- Starfleet frequency 1486 was the comm channel the USS Enterprise-E tied into to listen to the fleet's battle against the Borg in 2373. (Star Trek: First Contact)
- Top space frequency of 39 (TOS: "Mudd's Women")