The JBX43559 40m ST/APC to FC/UPC Simplex Singlemode Fiber Patch Cable represents professional-grade connectivity designed for mission-critical network applications. This single-strand cable bridges the gap between ST/APC and FC/UPC connector types, providing a seamless solution for systems requiring mixed connector configurations. **Superior Technical Specifications:** With a 9/125 singlemode core and G.657.A1 glass fiber composition, this cable achieves exceptional performance metrics. Insertion loss remains at ≤0.35dB (0.15dB typical), while return loss exceeds 20dB, ensuring minimal signal degradation over the 40-meter span. Attenuation specifications of 0.25 dB/km at 1310 nm and 0.35 dB/km at 1550 nm satisfy telecommunications-grade standards. **Construction and Durability:** The yellow riser-rated (OFNR) jacketing provides dual benefits: easy identification in complex installations and compliance with fire safety codes. At 1.8mm outside diameter, the cable navigates tight conduits and cable trays efficiently. Precision-engineered ST/APC and FC/UPC connectors deliver consistent, low-loss connections tested to ANSI/TIA/EIA-455-171-A-2001 standards. **Compliance and Availability:** Fully TAA compliant and RoHS/ELV certified, this cable meets government procurement requirements. The straight-through polarity ensures straightforward installation without specialized equipment. Custom lengths are available for applications requiring non-standard configurations. **Applications:** Ideal for telecommunications networks, data centers, long-distance LAN extensions, FTTH installations, and any application transmitting fiber signals across extended distances. The simplex configuration suits point-to-point transmission scenarios. **Shipping and Support:** Ships from multiple US locations (Danville CA, Fort Worth TX, Beaufort SC) with free standard shipping on orders exceeding $99. Backed by a 90-day limited warranty and manufactured in Taiwan, US, or China with consistent quality standards. **Why Choose This Cable:** When network reliability cannot be compromised, this cable delivers tested performance, regulatory compliance, and professional-grade construction in a compact, identifiable yellow package.