The JBX42066 4-meter LC/APC to SC/UPC duplex singlemode fiber patch cable represents a premium solution for professional-grade optical network infrastructure. Engineered with precision-manufactured components, this cable delivers reliable performance in critical telecommunications, data center, and enterprise networking applications. **Key Technical Features:** This duplex patch cable features a 9/125 singlemode fiber core construction, supporting long-distance, high-bandwidth optical signal transmission. The LC/APC connectors on one end and SC/UPC connectors on the other utilize Type A to B crossover polarity—the industry standard for duplex patch cord configurations. With insertion loss rated at ≤0.35dB (typically just 0.15dB) and return loss exceeding 20dB, signal degradation is minimized, ensuring superior optical performance. **Construction & Durability:** The cable features G.657.A1 glass fiber with a 1.8mm outer diameter jacketing, rated OFNR (Optical Fiber Non-conductive Riser). This riser rating enables safe installation in vertical cable runs and plenum spaces. The yellow jacket provides superior visibility for cable identification and management, reducing installation errors and simplifying network maintenance. **Compliance & Standards:** Fully TAA-compliant and RoHS/ELV certified per EU directive 2002/95/EC, this cable meets stringent regulatory requirements for government and enterprise procurement. All attenuation measurements are tested to ANSI/TIA/EIA-455-171-A standards, guaranteeing consistent performance across wavelengths (1310nm: 0.25dB/km, 1550nm: 0.35dB/km). **Availability & Support:** The JBX42066 comes with a 90-day limited warranty and qualifies for free standard shipping on orders exceeding $99. Custom lengths are available upon request for specialized deployment scenarios. Ships from multiple U.S. locations (Danville CA, Fort Worth TX, Beaufort SC) ensuring rapid delivery. **Ideal Applications:** Perfect for data center interconnections, telecommunications infrastructure, MPLS networks, and enterprise fiber-to-the-desk deployments. The precise connector combination and singlemode capability make it essential for long-distance, point-to-point optical links requiring minimal signal loss.