Abstract: Objective: The signal transmission of temperature controller for conventional dry\|type transformers using dry contacts suffers from severe interference, high cost, complex installation, and the need for additional power supply. The reliability and safety are compromised, making it difficult to meet the requirements of long\|distance signal transmission. To address this, the research focuses on intelligent terminals of dry\|type transformer for long\|distance communication (abbreviated as intelligent terminal). Method: Three technical solutions suitable for long\|distance communication (inter\|station distance greater than 4 km) dry\|type transformers are proposed, including Solution 1 (traditional ′hard wiring+intermediate relay′), Solution 2 (hard contact to optical signal transmission), and Solution 3 (optical fiber communication based on IEC 61850). A technical comparison of these three solutions is provided. Based on this analysis, the hardware and software requirements for Solution 3, as well as the networking and data flow, are further discussed. The key technologies for the development of intelligent terminal based on Solution 3 are also introduced. Finally, an engineering application of Solution 3 is demonstrated using a city′s rail transit line in China as an example. Result &Conclusion: Considering the requirements of long\|distance signal transmission on the long\|haul interval urban rail transit lines, Solution 3 should be prioritized. The test results from the example line show that intelligent terminal based on Solution 3 can effectively transmit signals and meet the safety requirements of power supply systems, while saving construction costs and significantly improving the intelligence level of dry\|type transformers. The advantages of fiber optic transmission, such as low latency, low cost, fewer transmission nodes, and immunity to electromagnetic interference, make it the mainstream mode of signal transmission in future urban rail transit systems.