The JBX42739 40-meter ST/APC to LC/UPC duplex singlemode fiber patch cable represents enterprise-grade connectivity engineered for demanding telecommunications and data center environments. This cable delivers reliable signal transmission over extended distances with minimal loss, making it an essential component for modern network infrastructure. **Technical Specifications:** This duplex cable features dual 9/125 singlemode fiber strands with G.657.A1 glass fiber specification, enabling high-bandwidth data transmission across metropolitan and wide-area networks. The 40-meter length provides flexible deployment options while maintaining signal integrity through low attenuation rates of 0.25 dB/km at 1310 nm and 0.35 dB/km at 1550 nm. **Connector Configuration:** The ST/APC to LC/UPC configuration represents the most common polarity pairing for duplex patch cords (Type A to B crossover). This versatile combination allows seamless integration with existing network infrastructure supporting these standard connector types. **Performance & Reliability:** With insertion loss ≤0.35dB and return loss ≥20dB, this cable meets rigorous ANSI/TIA/EIA standards ensuring consistent performance. The yellow jacket provides high visibility during installation and maintenance while the riser-rated (OFNR) jacketing ensures safety compliance in building environments. **Compliance & Certification:** Fully TAA compliant for government and enterprise procurement requirements. RoHS and ELV directive compliant (EU 2002/95/EC), this cable meets international environmental and safety standards. **Customization & Availability:** While this product ships as a standard 40-meter configuration, custom lengths are available to meet specific deployment requirements. Multiple US warehouse locations (California, Texas, South Carolina) ensure rapid shipping with free standard delivery on orders exceeding $99. **Applications:** Perfect for telecommunications networks, data center interconnections, campus area networks, and any fiber optic infrastructure requiring reliable duplex communication. The 1.8mm diameter allows efficient cable management and routing through conduit systems. **Warranty:** Backed by a 90-day limited warranty, providing peace of mind for mission-critical installations.