Fiber Optic Instrument Adapter SOC D4. SOC adapters provide direct connectivity for Tempo fiberTOOLS® to a wide range of industry-standard fiber optic connectors. Adapter design ensures maximum accuracy and repeatability when performing critical measurements on fiber optic systems. Easy to clean and use. Single-mode and multimode compatible. SOC adapters are compatible with both PC and Angled APC physical contact interfaces. SOC (Snap-On Connector) adapter is used on all power meters and 250 "B" series LED Sources.