DIRECT ANSWER / 01
OLTS verifies link loss; OTDR helps locate events
An OLTS measures path loss using a source and power measurement; an OTDR analyses returned signals to locate and characterise events. They are complementary tools: an OTDR trace is not automatically an OLTS acceptance report. First decide whether the project needs proof of total loss, event location or both.
Use this for site handover, troubleshooting and procurement test plans. Fluke’s strategy explains the complementary roles. MPO-terminated paths require a suitable method and compatible equipment. This guide does not prescribe a universal testing tier, pulse width or launch-fibre length; settings must match the link.
SELECTION MATRIX / 02
Purchasing decision matrix
| Item | Identify | Correct action | Avoid |
|---|---|---|---|
| Handover objective | Required loss, length, mapping or event evidence | Map each evidence item to a method | Specifying only an instrument name |
| OLTS | Endpoints, reference setup, fibre and wavelengths | Measure and record lanes under approved conditions | Replacing the agreed loss test with a trace estimate |
| OTDR | Dead zones, pulse, range, launch/receive fibres | Confirm target events can be assessed with the settings | Ignoring first/last event conditions |
| Prerequisites | Safety, end faces, interfaces and mapping | Inspect mating paths and reference cords first | Assuming a contaminated measurement proves a manufacturing defect |
| Records | Native files, settings, IDs and criteria | Retain reviewable evidence rather than screenshots alone | Keeping only a pass label |
RFQ INPUTS / 03
Minimum inputs a supplier can verify
| Category | Required input or confirmation |
|---|---|
| Equipment and scope | Instrument, wavelengths, fibre, ports, topology and directions |
| Method | Referencing, cords, OTDR settings, launch/receive fibres and standard revision |
| Outputs | Lane losses, required event data, native records and exception handling |
BUYER FAQ / 04
Purchasing FAQ
Can an OTDR replace an OLTS?
Not automatically. Principles and purposes differ; select the combination from contractual acceptance scope.
Does every project require both instruments?
Project requirements decide; this guide imposes no universal instrument pair. Agree both when both loss and event evidence are needed.
Is a PDF screenshot sufficient?
Follow the contract; retain native data and settings so exceptions can be reviewed.
Can any OTDR test MPO directly?
Do not assume so. Review instruments, interfaces, fanouts, lane selection, reference cords and methods.
How is launch-fibre length selected?
Review dead zones with actual settings, target events and fibre matching rather than using a universal length.
SOURCES / 05
Sources and applicability
Sources checked: 2026-10-02. This guide clarifies purchasing fields; it does not replace current equipment data sheets, full standards or the approved project drawing.