What feature must all firing systems have to prevent accidental firings?

A two-step interlock is a critical safety feature required in firing systems to prevent accidental firings. This system typically involves two distinct actions that must be initiated in sequence to engage the firing mechanism. This design minimizes the risk of an unintentional discharge of fireworks or special effects, as both steps must be consciously performed by the operator, ensuring that every firing is intentional and deliberate.

The two-step interlock system is essential in maintaining safety standards during the operation of fireworks displays. It acts as a safeguard that requires the operator to be engaged and attentive, reducing the likelihood of accidents due to distractions or mishandling.

In contrast, while emergency stop buttons, remote activation, and visual indicators are also important components in the context of firing systems, they serve different purposes. Emergency stop buttons provide a quick way to stop the system in an emergency, remote activation allows the operator to fire from a distance, and visual indicators give feedback regarding the system's status. However, none of these features specifically address the critical need to prevent accidental firings in the same proactive manner as the two-step interlock does.