The JBX42502 55-meter ST/APC to ST/UPC duplex singlemode fiber patch cable represents professional-grade connectivity designed for demanding telecommunications, data center, and enterprise networking applications. This precision-engineered cable combines superior optical performance with practical installation features. **Technical Performance:** Built on 9/125 singlemode fiber construction with advanced G.657.A1 glass technology, this cable delivers exceptional optical characteristics. The ST/APC to ST/UPC configuration provides Type A to B crossover polarity, the industry-standard for duplex applications. Insertion loss is rated at ≤0.35dB (0.15dB typical), while return loss exceeds 20dB, ensuring minimal signal degradation over the 55-meter span. Performance is verified against rigorous ANSI/TIA/EIA-455-171-A-2001 standards, with attenuation specifications of 0.25dB/km at 1310nm and 0.35dB/km at 1550nm. **Installation & Safety:** The 1.8mm outside diameter cable features riser-rated (OFNR) jacketing, meeting building code requirements for commercial installations without conduit protection. The bright yellow jacket enhances visibility during installation, troubleshooting, and future maintenance, reducing costly identification errors. **Compliance & Reliability:** TAA compliant for government and institutional procurement, this cable meets RoHS/ELV directives (EU 2002/95/EC), ensuring environmental responsibility and regulatory compliance. The 90-day limited warranty provides purchase confidence. **Flexible Solutions:** While this product is available in the standard 55-meter length, custom lengths are available for specific installation requirements. Multiple U.S. fulfillment locations ensure rapid shipping, with free standard shipping on orders exceeding $99. **Ideal Applications:** Perfect for telecommunications rooms, data centers, campus networks, broadcast facilities, and long-distance LAN connections requiring reliable singlemode performance.