| 摘要 |
<p>PURPOSE: To insert a lightweight optical fiber with no metal protective sheath therearound into a previously laid power or telephone cable having at least one ductlets forming a tubular directional path in the longitudinal direction by directing the optical fiber loosely into the ductlet. CONSTITUTION: A duct line 11 has at least one ductlet 12 forming a tubular directional path in the longitudinal direction into which an optical fiber 14 is loosely inserted, and at its center portion a core 13. The duct line 11 is made of an extruded polymer or another appropriate material, and the ductlet 12 is formed at the extrusion of the duct line 11. The center core 13 is adapted to be used for the testing operation of the duct line 11 being laid or having been laid, monitoring associated relays, power supply among others, and thus includes dedicated lead wire pairs. The duct line 11 and conductor wires for transmitting power or telephone signals are disposed in a power or telephone cable which is previously laid along the path of transmitting power or telephone signals.</p> |
