New IEEE Standard - Inactive-Reserved. The various existing technologies that are used or can be used to monitor the temperature of cable systems are reviewed in this guide. The conventional technologies, like thermocouples and resistance temperature detectors (RTDs), and the more recent technologies, like the distributed temperature sensing known as DTS, are covered. The latter technology is treated in more detail in this guide because it constitutes the logical and obvious choice for advanced and more accurate cable temperature monitoring where the hot spots along the cable route can be easily identified. This guide can also be considered as the first step that a potential user should consult before dealing with the issue of real-time rating of cable systems.