The information in this guide was obtained primarily through literature searches and market surveys. The vendors were contacted during the preparation of this guide to ensure the accuracy of data and information. In addition, the information contains test data obtained from other sources if available. The guide does not recommend specific equipment for purchase, but rather provides the reader with information available from vendors, so that commercially available equipment can be compared and contrasted. The guide first provides an overview of communication systems, with attention to system technologies, equipment types, accessories, and enhancements. This is followed by a section that discusses various characteristics and performance parameters that are used to evaluate communication equipment discussed in the guide. These characteristics and performance parameters are referred to as selection factors in the remainder of the guide. The selection factors are maximum transmitter output power, secure communications compatibility, programmability, user capability line of sight, power requirements, battery life, battery locking ability, vehicle adapter (portable radios), digital communications compatibility, durability, unit cost, operator skill requirements, and training requirements. The concluding section of the guide presents several tables that enable the reader to use the aforementioned selection factors to compare and contrast the communication equipment. Appendixes list questions that could assist emergency first responders when selecting communication equipment, list the documents referenced in the guide, and present information about communication equipment safety.