Solutions > Industrial Ethernet > The Critical Impact of Cable Type on Long-Distance Performance
The Critical Impact of Cable Type on Long-Distance Performance
Not all twisted-pair cables perform the same. The 10BASE-T1L standard itself does not mandate use of a specific cable type — it only specifies upper limits on cable insertion loss and return loss. This makes reuse of existing wiring possible, but also means different cables may perform very differently over long distances.
We tested two cable types:
Dedicated SPE Cable (Helukabel 82836)
This is an industrial-grade cable designed specifically for 10BASE-T1L, with excellent impedance characteristics. In the full 1,000-meter test, Classes 10 through 14 all operated normally with stable power performance — the preferred choice for long-distance deployment.
Traditional Telephone Wire (0.5 mm spec)
This type of cable exists in large quantities in many older buildings and factories, being the most common existing wiring. Test results showed that with low-voltage Classes (10–12, 24 V), available power at the PD end becomes extremely low beyond 800 meters; at 1,000 meters, the PD may even fail to start stably. However, switching to high-voltage Classes (13–14, 55 V), even with telephone wire spec, the PD end can still receive approximately 2.64 W of effective power after 1,000 meters, demonstrating the high-voltage mode’s advantage in compensating for voltage drop.
Core Insight
When planning 10BASE-T1L long-distance deployment, ‘cable selection’ and ‘PoDL Class selection’ must be considered together, not decided independently. Using existing telephone wire is feasible, but must be paired with an appropriate high-voltage PoDL Class, with rigorous power budget calculations performed.
FAQ
Q1
Can telephone wire (0.5 mm twisted pair) be used directly for 10BASE-T1L communication?
Answer
Yes, but field validation is required. Telephone wire’s impedance characteristics (approximately 100–120 Ω) are close to the SPE specification and can transmit 10BASE-T1L signals normally at certain distances. Measured data shows that 0.5 mm telephone wire can support both data communication and PoDL power delivery within 1,000 meters, enabling reuse of existing cable infrastructure and significantly reducing retrofit costs.
Q2
What are the main performance gaps between telephone wire and dedicated SPE cable?
Answer
The primary gaps are impedance consistency and high-frequency signal loss. Dedicated SPE cable strictly controls characteristic impedance (100 Ω ±15%) and is optimized for the 10BASE-T1L frequency band, delivering more generous signal margins; telephone wire has larger impedance tolerances, showing noticeably reduced Eye Diagram margin at longer distances, with lower power delivery efficiency due to its smaller conductor cross-section.
Q3
Is it recommended to use existing telephone wire when retrofitting buildings or factories for 10BASE-T1L?
Answer
Conditionally yes. Using existing telephone wire can significantly reduce cabling labor costs, but cable quality assessment must be performed first (measuring impedance and attenuation characteristics) and actual communication quality tested. If building wiring is heavily aged or shows large impedance deviation, selective replacement with dedicated SPE cable is recommended to ensure long-term reliability.
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