For first responders, such as firefighters, police officers and emergency medical technicians, a successful outcome to a mission—and perhaps the difference between life and death for them and those they are helping—depends on their communications system. Recognizing this critical need, first responders and emergency management officials have been calling for high-speed, LTE (Long-Term Evolution) cellular devices with three public safety “mission-critical voice” capabilities: “push-to-talk” for an immediate connection, “one-to-many” allowing an individual to broadcast to a large group, and “direct mode” that maintains a walkie-talkie connection when a wireless network is down, blocked or otherwise unavailable. To make this technology work effectively and ensure consistent product quality, the experts have already started developing standards.