The translink frequency is a specific frequency transmitted from interplexing beacons found in the cranial implants of Borg drones to communicate with the Borg Collective.
In an alternate timeline in 2390, Chakotay and Harry Kim requested that The Doctor extract the interplexing beacon from Seven of Nine in order to determine her translink frequency, which would, in turn, tell them where to send a message that they wished to transmit to the year 2375. The Doctor was later successful in finding Seven's translink frequency, noting that it was 108.44236000. (VOY: "Timeless")