Subspace communication
Subspace communication, subspace radio, or hyperchannel, was the primary form of electromagnetic communication used throughout the Federation. By transmission of a subspace radio signal, which traveled through subspace rather than normal space, subspace communication permitted the sending of data and messages across interstellar distances faster than the speed of light. This made it much more practical than conventional radio. In fact, starships rarely even monitored frequencies that traveled at the speed of light. (, okudagram; )

Subspace communication was mainly used by Starfleet Command to transmit orders to commanding officers of starships on deep-space assignments. Likewise, the vessels' commanding officers used subspace communication to relay reports on their various missions back to Starfleet Command, to ask for suggestions, and/or to make requests. (; ; ; ; ; et al.)

The speed of subspace messages varied greatly depending upon the technology involved.  For instance, in the 2260s, a subspace message from the Romulan Neutral Zone took three weeks to reach Starfleet Headquarters, whereas a century later, at the same distance, subspace communications were essentially in real time. (, ).  A message traveling subspace over a distance of 2.7 million light years would have taken fifty-one years and ten months to reach Federation space in 2364. ()

Depending on the actual distance between a vessel and the nearest subspace relay beacon, real-time communication was possible. An example of this is when Starfleet Lieutenant Reginald Barclay contacted the , which was seven light years away from his location on the Jupiter Station, and spoke real-time to the ship's counselor, Commander Deanna Troi. ()

Subspace communications had a varying degree of band frequencies, from upper (or high-band) to lower. For example, a diplomatic frequency used by the Vulcans was on a lower subspace band. (; )

Vulcans had been utilizing subspace communications as early as the Earth year 1957, as their ships were outfitted with subspace transceivers. ()

The Treaty of Armens set down EM spectrum communication as one of a number of acceptable means of communications between the Federation and the Sheliak Corporate in case something came up regarding the treaty. (, okudagram)

The practice of not sending out any subspace messages and ignoring any incoming transmissions was known as radio silence. ()

22nd century uses 

Earth had developed subspace communication as early as 2151. During this time, however, subspace amplifiers were required in order to maintain contact between Earth and Starfleet vessels over long distances. () Contact with these amplifiers was maintained with a single subspace antenna. If this antenna was damaged, a starship would only be capable of short-range communication. ()

Orders and reports were not the only communications to and from starships. Personal messages were also sent. The crew of Enterprise, for example, received personal messages from friends and family members back on Earth. Captain Jonathan Archer himself received recordings of water polo tournaments in what  described as the "subspace mailbag". ()

The treaty following the Earth-Romulan War was established entirely by subspace radio. No visual contact between the Humans, the Romulans, or their allies was ever established. () However, subspace communication was not available to all Earth ships during this period. The  was not able to communicate via subspace when the ship made contact with Sigma Iotia II in 2168. Thus, their report was not received by Starfleet Command until a hundred years later. ()

Before being destroyed, a group of Borg drones in the Alpha Quadrant sent a subspace message to the Borg in the Delta Quadrant in 2153. The message would have taken at least two hundred years to reach its destination and, if received, may have been the way the Borg of the 24th century learned of the existence and location of Earth. () In 2374, however, the  was able to communicate almost instantaneously between the Delta and Alpha Quadrants using a system of ancient relay stations, proving that subspace communication signals slow down over time unless amplified by a relay station. ()

23rd century uses
By the 23rd century, subspace communication was in wide use throughout the Federation. () During this time, a starship's communications officer was required to create subspace logs detailing all messages sent and received. ()

In some cases, marriages were performed entirely on subspace radio. Magda Kovacs and Ruth Bonaventure were married to two of the three miners on the Rigel XII mining colony via subspace radio in 2266. ()

After Fleet Captain Christopher Pike was injured upon being exposed to delta radiation, months of "subspace chatter" emerged regarding the accident. Later, in 2267, Spock fabricated a subspace message ordering the  to divert to Starbase 11 for the sole purpose of returning Pike, his former CO, to Talos IV where Pike could live out the rest of his days in comfort. During the subsequent court martial, Enterprise received subspace transmissions from Talos IV in violation of General Order 7. ()

Trelane of Gothos was able to block Enterprises subspace communications using his mirror machine. ()

The Eminians employed a subspace transmission unit to keep in contact with the Vendikans during their computer-fought war. This unit was tied in with Eminiar VII's attack computers. ()

24th century uses

By the 24th century, subspace communications were handled through subspace relay networks, replacing previous networking methods such as subspace amplifiers. These networks were maintained, at least in part, by various relay stations. ()

A 24th century professor, Doctor Paul Manheim, was renowned for his work in perfecting subspace communications. ()

Lore was able to communicate with the Crystalline Entity using subspace communications in 2364. However, a later encounter with the entity by the  required the use of graviton pulses for communication. ()

Unidentified subspace communications were detected by a class-1 probe that was sent to Nelvana III. ()

In 2369 Commander Benjamin Sisko sent a subspace message to Klaestron IV to verify the warrant of . ()

The same year, Chief O'Brien received a subspace message from his wife who visited the grain processing center in Lasuma on Bajor. Later, when Odo tried to contact Starfleet Headquarters, he learned that Major Kira had blocked all subspace communication. () 

In 2373, prior to the Dominion assault on Deep Space 9, Odo suggested that all outgoing subspace communication be terminated, in order to prevent security leaks. He prepared false messages to be transmitted at random intervals, so there would be no noticeable drop in DS9's outgoing subspace traffic. ()

See also
 Subspace differential pulse
 Subspace infrared algorithm

External link 
 

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