EuroWire July 2019

Technical Article

and distance correction in the facility information database. The newly developed system provides an automatic water penetration test function, cable length database correction function and repair work management function. Through these functions, engineers efficiently perform maintenance, and as a result, the quality of optical communication is maintained. n

and then search locations of water- penetration. In the proposed maintenance system, the OTDR waveform and the facility information are simultaneously displayed. This visualised function helps engineers estimate the penetrated location. Figure 4 shows the function of fibre length registration. Cable length registered in the facility management system is a design length. On the other hand, the OTDR waveform shows an actual length. As a result, cable length from the central office to water-penetrated closures does not match completely. The distance correction function is provided to fill the distance gap between the cable route planning information of the facility management system and the OTDR waveform. The correct cable length is updated by registering actual distance every time the engineer works on repairing the underground closure. According to the function, the accuracy of the cable length will be improved gradually along with the increase of the length correction information, once repaired. Repair records of the penetrated closures can be useful for searching locations of water penetration in the future. The important point is that every repair will be finished in the future. By utilising these functions, it will improve the efficiency of tasks in finding penetrated closures. 3.3 Function for searching locations of water penetration Conventional periodic test procedure is shown. 3.4 Repair work management function The conventional repair work is as follows. Since it takes time to find the water- penetrated closures and management of the penetrated closures is complicated, the repair completion rate is only 40 per cent. Until now, it was difficult to prioritise the repair work as NTT did not have the function to manage the penetration time of closures and progress of the repair work. The newly developed system has the function of managing the progress of the closure repair, the penetration time of closures, and fibre-splice type. This function allows engineers to develop efficient repair plans. 4 Conclusions Developed functions of the operation system are automatic periodic testing

5 Reference

[1] NTT “Financial Results for the Three Months Ended”, 30 th June 2017 [2] Enomoto Y, Izumita H, Mine K, Uruno S, Tomita N, “Design and performance of novel optical fibre distribution and management system with testing function in central office,” Journal of Lightwave Technology, Vol 29, No 12, 15 th June 2011 [3] Nakazawa K, Enomoto Y, Yamane T, Araki N, “Technologies for checking outside optical distribution equipment”, NTT technical review, Vol 7, No 11, November 2009 Courtesy of IWCS Cable and Connectivity Symposium, Rhode Island, USA, October 2018.

Strategic Network Management Department NTT East 19-2 Nishi-shinjuku, 3-chome Shinjuku-ku Tokyo 163-8019 Japan Tel : +81 3 5359 4450 Email : miho.akamatsu@east.ntt.co.jp

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July 2019