Most of the reference materials and application notes on in-building coverage solutions have focused on the booster technologies or system design architecture. One often overlooked aspect in the system design is the DAS implementation. This includes connecting all the cables and antennas throughout the building and balancing the signal levels at each DAS Services. If ignored, an improperly designed DAS results in degraded performance and unnecessary cost increases. This 2-part series of articles is an effort to outline a simple process of designing a DAS in order to achieve the most efficient RF coverage distribution. Part I talks about the Use of Directional Couplers in DAS and Part II covers the DAS Design Process.