The telecommunication industry is rapidly changing from predominantly regulated land lines to wireless technology that uses the same communications protocol (Internet Protocol or IP) as the datacenter industry. As a result, data centers and telecommunications facilities are converging. TC 9.9 uses the term “datacom” to indicate both data centers and telecommunication facilities. This chapter provides some basic information about data com facilities and where to find additional information. Datacom facilities provide space, power, cooling, and networking to datacom equipment (hardware). This chapter focuses on the equipment’s requirements, such as thermal, air quality, and power. USEFUL DATACOM RESOURCES DATACOM EQUIPMENT, POWER TRENDS, AND ENVIRONMENTAL GUIDELINES Datacom Equipment Workload Datacom Equipment Racks Datacom Equipment (Hardware) Datacom Equipment Components DATACOM FACILITIES GENERAL CONSIDERATIONS Air Cooling Liquid Cooling Water Usage Energy Efficiency