25 deals with general features in relation to the maintenance and operation of optical fibre cable networks. d suppliers of electrical construction services. Existence. Recommendation ITU-T L. This revision is intended to be appropriate for the current situation with respect to. We offer full-service OEM and ODM solutions for fiber optic cables, assemblies, and connectivity products — from design and prototyping to global production and logistics. Fiber optic testing of a newly installed system not only verifies that the system meets its design requirements, but also creates a performance baseline for all future testing and troubleshooting of t at system.