What model is the round-to-square pigtail fiber

A round-to-square pigtail refers to a fiber optic pigtail that has a round FC connector on one end and a square SC connector on the other end, allowing compatibility between different types of equipment and optical distribution frames (ODFs) or devices . The FC end usually connects to the ODF or older telecom equipment, while the SC end interfaces with the optical port of devices such as transceivers or switches . This type of pigtail was widely used in early SBS and Optix equipment and is still found in some legacy systems, including Huawei OSN series, ZTE S series, and early Lucent wavelength division equipment . The design ensures low insertion loss and stable optical signal transmission, combining the precision of a factory-terminated connector with the flexibility of field splicing to bulk fiber cables . In practice, round-to-square pigtails are used when connecting multi-core fiber cables to devices with differing connector standards, providing a reliable transition between older round FC interfaces and more modern square SC interfaces. Proper installation and splicing are essential to maintain network performance and minimize signal loss .