In the foreground producers constantly relay instructions to reporters in the field.

Once their location was measured and transferred to the sector plotting table, the controller would begin to relay instructions to the squadron leader.

Historically the bugle was used in the cavalry to relay instructions from officers to soldiers during battle.

The device allowed the coach to direct his quarterback on the fly, giving him an advantage over franchises who had to use messenger players to relay instructions.

The trumpet players were often among the most heavily guarded members of a troop, as they were relied upon to relay instructions to other sections of the army.