The pilot leagues each have access to several specific FTL communication channels for their alliances, in addition to generic interalliance channels that can be used by all.
The currently available channels open to all alliances are:
GENERAL COMMUNICATION
'TRA GEN [message]'
The primary interalliance channel, usable by any pilot from any alliance, as well as certain elements of alliance governments.
TACTICAL COMMUNICATION
'TRA TAC [message]'
An encrypted channel again usable by any pilot from any alliance, this channel tends to be used to give invasion warnings, reports of unusual events, and discussions of a nature that should not be made public by the leagues.
NEWBIE HELP
'TRA NEW [message]'
A vaguely OOC channel that exists only to allow new players to ask questions they could not otherwise ask on other channels due to the OOC nature of them, such as how to do things that ICly the character should know.
The currently available channels specific to alliances are listed below. To transmit on a channel, either tune your communicator to a specific channel (such as TUNE COMM TO 1, to tune it to Alliance Communication, and use TRA [message] to speak on it, or TUNE COMM TO 0 to set your comm to the tuner, and use TRA 1 [message] for Alliance Communication, TRA 2 [message] for Distress, etc.)
CHANNEL 1 = ALLIANCE COMMUNICATION
This is the primary alliance-specific channel, used by most pilots to speak with other members of their alliance's pilot league.
CHANNEL 2 = TACTICAL
This channel is, as the name implies, for tactical discussion, emergency responses and so on.
CHANNEL 3 = TRADE INFORMATION
This channel is for trade-related discussion or requests.
CHANNEL 4 = SECTOR STATUS
This channel is for information relating to the status of all sectors controlled by your alliance.
CHANNEL 9 = RADIO CHANNELS
These channels, slightly different for each alliance, are radio channels, specific to each alliance.
CHANNEL 10 = CONQUEST STATUS
This channel is used to periodically determine the alliance's current Conquest status.
Channels 5, 6, 7 and 8 are currently not used for specific purposes, but are usable as if they are normal channels.