Which connector port requires a 1.25 mm swab for cleaning on an OTDR?

The LC connector requires a 1.25 mm swab for cleaning because it is designed with a smaller ferrule diameter than other types of connectors. The LC connector features a 1.25 mm ferrule, making it more compact and suitable for high-density applications within telecom and data centers. The specific size of the swab is crucial for effectively cleaning the connector without damaging it or leaving residue, which could affect the performance of the optical link. In contrast, other types of connectors like SC, ST, and MPO have larger ferrule sizes, which would require different cleaning tools. The precise matching of cleaning tools to the size of the connector's ferrule ensures optimal performance and reliability of the optical connection.