Tactical communications are communications in which information of any kind, especially orders and decisions, are conveyed from one command, person, or place to another within tactical forces. In modern times, this is usually done by electronic means.
Before the time of electronic equipment the way of communicating on the battlefield was to use either drums, trumpets or flags. Each sound or banner would then have a significance for the soldier who would respond accordingly.
Communication between armies were of course much more difficult before the electronic age and could only be achieved with messengers on horseback or by foot and with time delays according to the distance the messenger needed to travel. Intricate warning systems have though always been used such as scouting towers with fires to signal incoming threats.
Tactical communications do not include communications provided to tactical forces by the Defense Communications System to non-tactical military commands, and to tactical forces by civil organizations.