The JBX42606 4-meter FC/APC to ST/UPC duplex singlemode fiber patch cable represents a premium solution for network professionals requiring reliable, high-performance fiber connectivity. This industry-standard cable is engineered to support critical telecommunications and data center applications where signal integrity and consistency are paramount. **Key Technical Specifications:** Features a robust 9/125 singlemode fiber core constructed from G.657.A1 specification glass fiber, delivering exceptional attenuation performance at both primary telecommunications wavelengths (1310nm: 0.25dB/km and 1550nm: 0.35dB/km). With insertion loss rated at ≤0.35dB (typical 0.15dB) and return loss ≥20dB, this cable ensures minimal signal loss across connection points, critical for long-distance transmissions and sensitive optical applications. **Connector Configuration:** The FC/APC to ST/UPC duplex configuration uses Type A to B crossover polarity, the industry-standard pairing for duplex patch applications. This crossover design ensures proper signal flow in bidirectional communication systems, making it ideal for Ethernet, SONET, and other duplex fiber network protocols. **Construction & Durability:** The cable features a bright yellow OFNR (Optical Fiber Non-Conductive Riser-rated) jacket, providing excellent visibility in cable management systems while meeting NEC building code requirements for in-building installations. The 1.8mm outside diameter offers flexibility for tight routing while maintaining durability and crush resistance. **Compliance & Certifications:** Fully TAA (Trade Agreements Act) compliant for government procurement applications. RoHS/ELV certified in accordance with EU Directive 2002/95/EC, ensuring environmentally responsible manufacturing. Attenuation testing meets ANSI/TIA/EIA-455-171-A-2001 standards, guaranteeing performance consistency and reliability. **Flexible Solutions:** While this 4-meter standard length addresses most installation needs, custom lengths are available for specialized applications, allowing precise cable management and reducing waste. Multiple domestic warehouse locations (Danville CA, Fort Worth TX, Beaufort SC) ensure rapid fulfillment with free standard shipping on orders exceeding $99. **Ideal Applications:** Perfect for data center interconnects, telecommunications networks, medical imaging systems, industrial process control, and any application requiring single-mode fiber transmission with duplex capabilities. The FC/APC connector pair is particularly valued for its durability and low-reflection characteristics in precision optical systems. **Warranty & Support:** Backed by a 90-day limited warranty, providing confidence in product quality and performance.