Physical access control has remained a critical front-line defense for organizations of all sizes. Swipe cards, proximity cards, and key fobs are now commonplace in many office environments. However, as technology advances and convenience becomes an increasing priority, the concept of mobile access has become ever-present in today’s office environment. Using a mobile device to access a building is about merging security with convenience. Understanding the nuances of opening a door with a phone will enable you to make better choices about how best to implement mobile access successfully.