A cranial transciever is an implant within the brain of every Borg drone, each containing a unique translink frequency, the translink frequency of Seven of Nine for example was: 108.44236000. Enabling communication with that specific drone akin to a technologically induced form of telepathy - the communications are interpreted as voices in their mind. Whilst the communication is primarly answered via though-based response it is equally capable of picking-up spoken responses.