These red boxes you see on street corners are fire alarm call boxes, part of a citywide system installed in the late 1800s. Long before phones existed. If someone spotted a fire, they could break the glass and pull the lever to alert the fire department immediately. Each box is connected to an underground network and sends a coded signal that tells San Francisco Fire Department the exact location of the alarm. While cell phones are now the primary way to report emergencies, many of these boxes a