Notes : The Federation issued a requirement for a new design of subspace communications relay station in 2352 in order to replace the Mark IX then in production. The requirement called for a station able to handle more than three times the information flow capacity as the Mark IX, and to include all the latest and projected scrambling and encryption systems. In addition the new station would include a higher accomodation standard and would require less frequent resupply stops.

The design proceeded smoothly, and the first of the stations was completed in 2354 and added to the network later in the same year for a one year trial period. The relay performed flawlessley, and by late 2355 series production had begun. By 2364 some 500 stations per year were being added to te network, and by 2370 this had risen to 1,250. In service these stations have proved to be highly reliable and effective.

With the advent of the Dominion war, many of the relay stations adjacent to combat zones have been relocated in order to prevent the Dominion from destroying them. Many of these have been put into storage until the end of the war, but most have been relocated to improve coverage in hitherto low priority areas.