The JBX42319 SC/APC to FC/UPC duplex singlemode fiber patch cable represents professional-grade connectivity for modern fiber optic networks. This 40-meter cable is specifically designed for applications requiring precise signal transmission and minimal attenuation in single-mode fiber environments. **Key Technical Features:** The 9/125 singlemode core supports long-distance, high-bandwidth applications typical in telecommunications and data center environments. With an outer diameter of just 1.8mm, the cable remains flexible while maintaining structural integrity. The G.657.A1 glass fiber specification provides superior performance characteristics, with attenuation rates of 0.25 dB/km at 1310nm or 0.35 dB/km at 1550nm—ideal for both short and long-haul applications. **Connector Specifications:** The SC/APC (straight physical contact) connector features a polished angled endface, providing superior return loss and minimal reflectance. The FC/UPC (ultraphysical contact) receiver offers secure threaded connection with excellent repeatability. The Type A to B crossover polarity ensures compatibility with standard duplex installation configurations. **Performance Standards:** Attenuation testing complies with ANSI/TIA/EIA-455-171-A-2001, with typical insertion loss of only 0.15dB and return loss exceeding 20dB—exceeding industry requirements for premium fiber installations. **Safety & Compliance:** Riser-rated (OFNR) jacketing meets fire code requirements for in-building use. RoHS and ELV compliant construction eliminates hazardous substances. TAA compliance ensures eligibility for government and regulated procurement processes. **Practical Advantages:** The distinctive yellow jacket simplifies cable identification and organization within dense fiber environments. Duplex configuration supports bidirectional communication in a single compact connector pair. The 40-meter length covers substantial distances without intermediate splices, reducing connection points and potential signal degradation. **Use Cases:** Ideal for telecommunications networks, data center backbones, campus network interconnects, and any application requiring reliable single-mode fiber connectivity with minimal insertion loss. Custom lengths available for unique installation requirements. **Warranty & Support:** 90-day limited warranty provides confidence in purchase. Free standard shipping on orders over $99 from multiple US locations ensures rapid delivery. Professional-grade construction guarantees long-term reliability in mission-critical applications.