This form of magic allows the user to transmit and project auditory and visual information. In order to use it to its full potential, specific spells are required, which are stored within grimoires.
For communication over long distances, the user must have previously marked the place or person with their magic. Through unknown means, this marking can be blocked so as not to be disturbed or tracked.
For those mages unable to use this type of magic on their own, there exist devices that enable long-range telecommunication, called Communication Magic Tools 「通信魔導具 Tsūshin Madōgu, Viz: "Magic Communication Items, Transmission Magic Items"」. Magic Knight squads have several to keep in contact with Knights away on missions, and only some of the devices transmit visual as well as audio. These devices do not require the user to supply it with magic, so people with little to no magic power or with poor magic control could make use of them.