A fiber-optic cable acceptance test is a field protocol that verifies an installed optical link will carry the protection, control, or communication traffic it was built for before that traffic is entrusted to it. It records the link's identification (manufacturer, cable type or part number, fiber type as single-mode or multimode, fiber count, connector type, nominal cable length, the origin and destination of the run, and the equipment designation), then works through a visual and mechanical inspection and four optical measurements. The inspection compares cable, connector, and splice data with the drawings and specifications, looks for physical and mechanical damage, confirms connectors and splices are correctly installed, and confirms no bend in the run is tighter than the manufacturer's minimum bending radius. The optical work uses an optical time-domain reflectometer to establish the measured length of the fiber and to look for fractures and construction defects, then to examine connector and splice integrity along the same trace; measures cable attenuation loss at a stated test wavelength; measures connector and splice attenuation loss from both ends of the link; and measures transmit and receive power at the local and the remote device. NETA ATS-2025 section 7.25 lists this as the standard acceptance sequence for fiber-optic cables.
An optical fiber is a glass path with no electrical signature to inspect, so a defect in it cannot be found the way a cable fault is found on a copper circuit. A fiber that was pulled around too tight a corner, crushed in a duct, or terminated with a contaminated connector will still pass light, just less of it, and the link will work on the bench and fail at the margin months later when temperature or a second splice takes the last of the budget. The acceptance test exists to measure that margin while it can still be corrected. The reflectometer trace locates a fracture or a lossy splice by distance, so a fault can be dug up at the right place rather than along the whole run; the attenuation measurements establish the loss per unit length against what the manufacturer says the cable should deliver; and the transmit and receive power readings confirm the optics at each end are inside their own operating window. On a protection or teleprotection link, this is the difference between a scheme that trips in cycles and one that does not communicate at all.
Acceptance: after the cable is installed, terminated, and spliced, and before the link is put into service, as part of the standard acceptance sequence. The same form carries a maintenance service type, because the optical measurements are repeated periodically once the link is in service and after any event that disturbs the route, such as civil works along the duct, a re-splice, or a connector replacement. Measuring from both ends is part of the method rather than a repetition, since connector and splice loss reads differently depending on which end the instrument launches from. The maintenance edition of the standard also expects the readings to be compared against the previous set, so the first acceptance record becomes the baseline every later visit is judged against.
With the link out of service, the cable, connector, and splice data is compared with the drawings and specifications, the run is inspected for physical and mechanical damage, connectors and splices are confirmed correctly installed, and every accessible bend is checked against the manufacturer's minimum bending radius. The optical time-domain reflectometer is then launched into the fiber and the reflected power against distance trace is recorded: the measured length is read from the trace and compared with the nominal length, and the trace is examined for fractures and construction defects and for the signature of each connector and splice along the route. Cable attenuation loss is measured at the stated test wavelength and expressed per kilometer, and connector and splice attenuation loss is measured from both ends of the link so each termination is characterized from the near side. Transmit and receive power is then measured at the local device and at the remote device, giving four readings that bracket the optical budget of the link. The manufacturer's published data for the cable, the connectors, and the end devices is recorded alongside the measurements so each reading has its reference value next to it. Ambient temperature, relative humidity, and the test equipment used, with its calibration due date, are recorded with the results.
The link identification (manufacturer, cable type or part number, fiber type, fiber count, connector type, nominal cable length, origin and destination, and equipment designation); the result of each visual and mechanical inspection item, including the bending-radius check; the measured cable length from the reflectometer trace together with the fracture and construction-defect findings and the connector and splice integrity findings; the test wavelength, the measured cable attenuation loss, and the manufacturer's recommended maximum for that cable; the connector and splice attenuation loss measured from each end with the manufacturer's recommended maximum; the transmit and receive power at both the local and the remote device with the manufacturer's published data used as the reference; and the ambient temperature, relative humidity, test equipment with calibration due date, comments, and any deficiencies found.
The standard publishes no numeric loss limit for this section, which is the single most important thing to understand about evaluating a fiber link: the manufacturer's recommendations govern, and the site specification governs where one exists. Physical and mechanical damage, incorrect connector or splice installation, and a bend tighter than the manufacturer's minimum radius are all findings that fail on their own terms. The reflectometer results are evaluated by analyzing the trace itself, backscatter along the fiber for the length, fracture, and defect findings, and the step at each termination for excessive connector or splice attenuation, rather than by comparing a single number to a table. Cable attenuation loss is expressed per kilometer and is acceptable when it falls inside the manufacturer's recommendation in the absence of a local site specification, and connector and splice attenuation loss is judged the same way from each end. Transmit and receive power is compared with the manufacturer's published data for the devices at each end. The maintenance edition of the standard also expects comparison against the previous test results, and it expresses connector loss and splice loss in different units than the acceptance edition, so read the edition you are working to. See the purchased NETA standard and the cable and device manufacturers' published data for the values that apply to a given link.
UltraDb references ASTM, ANSI, IEEE, and NETA standards descriptively, to identify the published methods its forms are built from. UltraDb and Entigy Solutions are not affiliated with, endorsed by, certified by, or licensed by NETA, ASTM, ANSI, IEEE, or Megger. Standard names and section numbers are the property of their respective organizations. Always test to the edition your contract specifies.