Mode Conditioning Patch Cord

LC stands for Lucent Connector. The LC is a small form-factor Fiber optic connector.
The LC Connector uses a 1.25 mm ferrule, half the size of the SC. Otherwise; it is a standard ceramic Ferrule connector. The LC has good performance and is highly favored for single mode. APC polish is with an angle for 8 degrees in the ferrule.

ST stands for Straight Tip – a quick release bayonet style Connector developed by AT&T. STs were predominant in the late 80s and early 90s.