Subspace channel
A subspace channel was a communication channel consisting of a designated band of subspace frequencies, or single dedicated subspace 

According to Spock, as of 2267, beyond the region of Cestus III existed only "rumors of certain strange signals on subspace channels. However, none has ever been recorded." ()

Lore transmitted on a subspace channel from aboard the  to contact the Crystalline Entity in 2364. ()

Data later blocked every subspace channel after he had commandeered the USS Enterprise-D in 2367, making it impossible for the rest of the crew to call for help. ()

In an later effort for Captain Jean-Luc Picard to locate the rogue , he had Worf transmit priority one communique that contained "a repeating message on all subspace channels" for the Phoenix to "Break off your pursuit immediately." () 

Later yet that year, Picard once again had Worf transmit another priority one communique that contained "a repeating message on all subspace channels" that ordered Lieutenant Paul Hickman aboard the Federation shuttlecraft to "come about and stand to." ()

A convoy of Vulcan ships that crossed the Romulan Neutral Zone responded to a subspace message from the Enterprise-D that stated their intentions, and that further requested that the Enterprise "monitor Federation subspace channels," as "Ambassador Spock will be making an announcement shortly." When it was transmitted a short time later, the announcement came in "from Romulus on all subspace channels." ()

Due to the sensitive nature of the mission the USS Enterprise-D was assigned to, following their rendezvous with the  in 2370, Vice Admiral Margaret Blackwell explained to Captain Picard that she preferred not to discuss the matter over subspace channels. ()

The same year, the  replicant requested the runabout's computer to open a subspace channel to Starbase 410 to send a priority one message to Admiral Rollman. ()

List of subspace channels 
 Channel B
 Channel D
 D channel
 Emergency Channel D
 Channel E
 Channel 1
 Channel 3
 Subspace coded channel 98.8
 Emergency channel 0130

channel
Communications technology