Fiber loopback cables provide system test engineers a simple but effective way of testing the transmission capability and receiver sensitivity of network equipment. The hardware loopback plug test is used to see if the router has any faults. If a router passes a hardware loopback plug test, then the problem exists elsewhere on the line. When a serial line does not come up as it must, the best way to troubleshoot the circuit is to perform loopback tests. Loopback tests allow you to isolate pieces of the circuit, and test them separately. Begin loopback tests on the customer premises with channel service unit/data service unit (CSU/DSU) loopback tests. Then proceed on to loopback tests that involve the telco or provider. Two kinds of loopback tests can be used to isolate problems on the serial link: software loopbacks and hardware plug loopbacks. Whether it is an internal or external CSU/DSU, you can do both software and hardware loopbacks back towards the router.Software local loopbacks are usually implemented with a Cisco IOS configuration command, or with a loopback button for some CSU/DSUs. A loopback plug or cable inserted into the CSU/DSU can be used for hardware loopbacks.If CSU/DSU loopback tests prove that the router equipment, CSU/DSU, and connecting cables are not faulty, conduct further tests with the telco or provider of the circuit.
There are several types of fiber loopback cables, such as LC, SC, FC, MTRJ. The LC fiber optic loopback cables are used in test applications LC fiber optic loopback cable connector feature the RJ-45 style interface with low insertion loss and low back reflection, it is with high precision alignment and is widely used all over the world. LC loopback cables can be 9/125 single mode or 50/125 multimode or 62.5/125 multimode. The LC fiber loopback cable connector is with a 1.25mm O.D zirconia ceramic ferrule and it is compliant to Telcordia, EIA/TIA and IEC standards. LC loopback cables are designed for testing, engineering and the burn-in stage of boards or other equipment. One connector is plugged into the output port, while the other is plugged into the input port of the equipment.
FiiberStore supply loopbacks which are precision terminated and feature extremely low loss characteristics for transparent operation in the test environment and in form of cable and module types. 10G OM3, Singlemode and Multimode fiber optic loopback modules are available.