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.
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 ST. Otherwise; It is a standard ceramic Ferrule connector. The LC has good performance and is highly favored for single mode.
Features:
Low insertion loss(≤ 0.20dB)and high return loss(≥ 55 dB) Free-floating ceramic ferrule UL-rated plastic housing and boot Boots in a variety of colors High precision alignment connector
Applications:
Local Area Networks (LANs) and Wide Area Networks (WANs) Fiber Optic CATV, FTTH, FTTB, FTTP etc Fiber Optic telecommunication systems Transmission Mode (ATM) Fiber Optic Backbone Military Instrumentation