A regional fiber network maintenance service provider had long focused on metro and access networks. While experienced in routine maintenance tasks, the company had limited exposure to long-haul backbone testing.
As competition intensified, more projects began requiring:
- Accurate fault localization over 100 km+ fiber links
- Detection of low-loss events and subtle anomalies
- High-efficiency testing within limited maintenance windows
Without upgrading their testing capability, the company risked being excluded from higher-value backbone projects.
The Challenge
Long-distance fiber networks—especially those deployed years ago—often present hidden issues that are difficult to detect with conventional testing equipment.
In this case, the company was tasked with inspecting a railway communication backbone line in southern Asia. The project posed several challenges:
- The fiber route spanned multiple regions and complex terrain, including long tunnel sections
- Many splice points were poorly documented or unknown
- The network had been in operation for years, increasing the likelihood of latent attenuation issues
- Maintenance windows were extremely limited, requiring fast and reliable testing
Traditional OTDR solutions struggled to provide both long-distance coverage and sufficient resolution for identifying subtle defects.
The Solution
After evaluating several options, the company deployed the TFN RM7 Series OTDR with 50 dB high dynamic range.
Key capabilities included:
- Stable signal acquisition beyond 100 km
- High sensitivity for detecting minor loss variations
- Integrated modular design combining OTDR, optical power meter, and distance measurement
- On-device data analysis and annotation for immediate decision-making
Field Performance & Findings
The RM7 quickly proved its value during real-world testing.
Even at distances exceeding 100 km, the device delivered clear and stable end-of-line signals, allowing the team to confidently assess overall link integrity.
A particularly challenging section involved a long tunnel cluster, where environmental conditions and aging infrastructure increased the risk of hidden defects.
During analysis, engineers observed a subtle step change in the OTDR trace. While the variation was small, its shape differed from a typical splice signature.
After zooming in, the team identified:
- An abnormal loss of approximately 0.2 dB
- A slight reflective characteristic, indicating a potential structural issue
A subsequent on-site inspection confirmed the cause:
- Aging sealing components inside the tunnel splice enclosure
- Minor fiber bending leading to gradual signal degradation
Left unaddressed, this issue could have evolved into a future fiber failure.
Efficiency Gains in Real Operations
Railway communication systems allow only short maintenance windows, requiring teams to complete multiple testing tasks under tight time constraints.
According to one field engineer:
“In the past, we had to carry multiple devices—OTDR, power meter, distance tools—just to be prepared. With the RM7, everything is integrated into one unit. It significantly reduces setup time and keeps the workflow smooth during high-pressure testing windows.”
The integrated design helped:
- Reduce equipment switching and setup time
- Maintain testing rhythm during intensive field operations
- Improve overall operational efficiency
From Rough Estimates to Actionable Data
The impact of the RM7 extended beyond field testing.
Previously, reports often reflected general network conditions. With the RM7, the team could now deliver:
- Precise fault locations
- Clear identification of potential risk points
- On-site preliminary analysis without returning to the office
As the technical manager noted:
“Our reports have evolved from rough assessments to accurate, actionable records. We can now identify and verify issues directly in the field, which saves time for us and provides immediate value to our clients.”
Business Impact
Since adopting the RM7 Series OTDR, the company has successfully:
- Entered high-end backbone testing projects
- Independently delivered multiple long-haul inspection assignments
- Strengthened its competitiveness in advanced network testing scenarios
Scénarios d'application
The RM7 high-dynamic-range OTDR is not designed for routine testing, but for demanding, high-precision applications, including:
- Railway communication backbone networks
- Telecom operator long-haul fiber lines
- Power grid communication systems
- Defense and critical infrastructure fiber networks
Conclusion
For service providers aiming to move up the value chain, upgrading testing capability is essential.
The TFN RM7 OTDR offers a practical path to:
- Extend testing distance beyond traditional limits
- Detect subtle issues before they escalate
- Deliver faster, more reliable results in the field
Ultimately, it enables teams to transition from basic maintenance providers to high-end solution partners.