Welcome to WireXpert Loopback Setup & Testing Training
Course Duration: 35–50 minutes
Sometimes you're on your own, or the REMOTE unit is somewhere else. This module covers what the WireXpert MP can do with only the LOCAL unit (fiber single-ended loopback and the copper Single Ended Test), where those results stop being valid, and how to keep the references behind every result trustworthy. It builds on Softing WireXpert MP Cable Tester and Dual-Ended Testing training.
What You'll Learn:
- Tell apart fiber loopback, copper single-ended testing, and certification
- Set up and reference fiber single-ended loopback
- Interpret a loopback result against a loop budget
- Use the copper Single Ended Test appropriately
- Keep references and test cords trustworthy, and keep records
Course Structure
- What “Loopback” Means on the WireXpert MP
- Fiber Single-Ended Loopback: Setup & Reference
- Running a Fiber Loopback Test
- Copper Single-Ended Test
- Keeping References Trustworthy
- Troubleshooting & Records
- Final Assessment — 10 questions, 80% (8 of 10) to pass
Each section ends with a knowledge check. You get two attempts, and a first miss gives you a hint, not the answer. Finish the check to unlock the next section. You'll enter your name and email just before you submit the final assessment. Your results are emailed automatically to the training administrator, with a copy to you, whether you pass or not.
Section 1: What “Loopback” Means on the WireXpert MP
“Loopback” means testing with only the LOCAL unit: the signal leaves the tester and comes back to the same tester instead of being received by a REMOTE unit. On the WireXpert MP, this shows up in two places, and it's important to know what each one can and can't do.
| Function | What it is | Certification? |
|---|---|---|
| Fiber single-ended loopback | A fiber test mode. You set the reference and run the AUTOTEST with only the LOCAL unit; light leaves its TX port and returns to its RX port. | Tier 1 loss of the loop, when the project allows loopback testing |
| Copper Single Ended Test | Uses only the LOCAL unit, sometimes with a termination plug at the far end. It needs Custom limits and is disabled by default. | No. It's a troubleshooting aid. |
| Copper certification | Always dual-ended: LOCAL plus REMOTE | Yes |
| Loopback / single-ended | Dual-ended | |
|---|---|---|
| Units | LOCAL only | LOCAL + REMOTE |
| People | One technician | One or two technicians |
| Best for | Fiber loops, cord checks, quick troubleshooting | Copper certification; per-fiber certification |
| Limitation | Can't tell which part of the loop has the loss | Needs both units at opposite ends |
Section 2: Fiber Single-Ended Loopback: Setup & Reference
Know the ports
On the MP FQ (quad) fiber module, facing the touchscreen, the ports run left to right: TX singlemode, RX (shared by both fiber types), and TX multimode. The FM (multimode) and FS (singlemode) modules have one TX port each.
Setup
- Inspect, clean, and re-inspect every test reference cord (TRC) end-face before connecting it.
- Under Test Settings, choose Single-ended loopback as the test mode, then set the fiber type, limit, and reference method.
- For the reference, connect a test reference cord from the LOCAL unit's TX port back to its own RX port, so the light loops back into the same unit.
- Run Tools › Set Reference and check that the reference reading falls inside the acceptance range for your fiber type.
| Fiber type | MP set-reference acceptance range (quick reference guide) |
|---|---|
| Singlemode | −5.35 to +4 dBm |
| Multimode | −25.35 to −15 dBm |
Section 3: Running a Fiber Loopback Test
How the loop is built
- Disconnect the TX and RX cords from each other only at their free ends, never at the tester.
- Connect the TX cord to fiber 1 at the near-end panel, and the RX cord to fiber 2 at the same panel.
- At the far end, join fiber 1 to fiber 2 with a short, clean loopback jumper.
- Press AUTOTEST. The light travels out on fiber 1, crosses the loopback jumper, and returns on fiber 2.
What the result means
The reading is the combined loss of both fibers plus the far-end loopback connections. Compare it with a loop budget that adds up both fibers' budgets plus the loopback jumper's connections. Don't compare it with a single-fiber budget.
| Good uses | Limitations |
|---|---|
| Testing a duplex link when you're working alone | If the loop fails, you can't tell which fiber (or the jumper) is responsible |
| Checking patch cords and test cords | A low-loss fiber can hide a marginal one in the total |
| Quick go/no-go checks during troubleshooting | Many project specifications and warranty programs require per-fiber, dual-ended results |
Section 4: Copper Single-Ended Test
The copper Single Ended Test runs from the LOCAL unit alone. Depending on the measurement, it may need a termination plug at the far end. It's disabled by default and requires Custom limits, which is a reminder that it isn't a standards-based certification.
When it helps
- A REMOTE unit isn't available, and you need a quick look at a suspect run
- Finding a gross fault, such as a cut, an open, or a short, before you bring the REMOTE unit back
- Checking a cable on the reel or a run in progress, before it's terminated for certification
When it doesn't
- Customer acceptance or warranty reports: these need a dual-ended AUTOTEST against TIA or ISO limits
- Any decision based on NEXT or return loss at the far end, which a single-ended test can't see
Section 5: Keeping References Trustworthy
Every loss figure is measured against a reference. A bad reference quietly corrupts every result that follows, so this section is about keeping references trustworthy.
Copper: Set Reference
- Done with a permanent link adapter on LOCAL, a channel adapter on REMOTE, the kit's reference cord, and the DCRU calibration artifact steps.
- Repeat it after first pairing, firmware updates, adapter changes, long idle periods, or big changes in environment.
Fiber: reference and TRC Verification
- Check that the reference reading falls within the acceptance range.
- Use TRC Verification to prove the test reference cords with a second set through a coupler.
- Re-reference if a cord is unplugged at the tester, the cords are changed, or the reading drifts.
Reference vs. calibration
Set Reference is a field step. It doesn't replace Softing's annual calibration, which keeps the instrument itself traceable. Keep the calibration certificate with the kit.
Section 6: Troubleshooting & Records
Troubleshooting
| Symptom | Likely cause | Action |
|---|---|---|
| Fiber reference outside the acceptance range | Dirty or damaged cord end-face, a bad cord, or the wrong port | Inspect, clean, and re-inspect; replace the cord; check you're on the right TX port; re-reference |
| Loop loss higher than the loop budget | A dirty connection somewhere in the loop, a bad loopback jumper, or one high-loss fiber | Clean and retest; swap the loopback jumper; then test each fiber dual-ended to isolate it |
| Results change between identical runs | Cords moved during the test, a contaminated connector, or a reference unplugged at the tester | Keep cords still, clean the connections, and re-reference |
| Copper Single Ended Test won't run | It's disabled by default, or no Custom limit is selected | Enable it and select a Custom limit, and remember it isn't certification |
| Golden link drifting over weeks | Adapter or cord wear, or contamination | Replace worn LongLife cords or adapters, clean, re-reference; then call service if it persists |
Records
Log every reference check and golden-link test with the date, tester serial number, firmware version, the cords or adapters used, the result, and any action taken. Keep the records for as long as the project contract or warranty program requires. There's no single industry-wide retention period, so check the project documents.
Final Assessment
Answer all 10 questions. You need 80% (8 of 10) to pass. These questions are different from the section knowledge checks. Enter your name and email below the questions, then submit.
Your Information
When you submit, your results are emailed automatically to the training administrator, and a copy is sent to the email address you enter here — whether or not you pass.
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