The Federal Communications Commission has adopted an order aimed at helping first responders locate 911 callers in multi-story buildings. The order adopts a z-axis (i.e., vertical) location accuracy metric of plus or minus three meters relative to the handset for 80% of indoor wireless 911 calls. The vertical accuracy requirements will be phased in starting in April 2021. The Commission is also seeking comment on establishing a long-term timeline for even more stringent vertical location accuracy, including a requirement that carriers provide public safety answering points with floor level accuracy.