Is the FC pigtail round or square

The FC (Ferrule Connector) pigtail is characterized by its round, screw-on design made from metal, typically nickel-plated or stainless steel, which provides a secure and vibration-resistant connection . Unlike SC or LC connectors, which have a square or rectangular housing, the FC connector uses a threaded collet to mate with the adapter, ensuring precise alignment and stability, especially in high-precision or high-vibration environments .

• SC Pigtail: Square-shaped connector with a plug-and-jack latch mechanism, commonly used in telecom and outdoor networks .
• LC Pigtail: Small square connector, snap-on type, often used in high-density ODFs .
• FC Pigtail: Round connector with threaded coupling, ideal for laboratory equipment, OTDRs, and applications requiring precise alignment and vibration resistance .

FC pigtails are typically used in single-mode fiber networks, test labs, and precision measurement setups where stable, low-loss connections are critical. They are less common in modern telecom deployments compared to SC or LC connectors but remain valuable in environments where mechanical stability and alignment accuracy are essential . In summary, if you are selecting a pigtail for an FC interface, you should expect a round connector, which distinguishes it from the square SC or LC types.