The UJ (Universal Joint) and UC (Universal Coupling) are used in medium and long-haul submarine networks where repeaters or optical amplifiers are deployed.
The UJ provides a connection between cables and the UC provides a connection between a cable and submerged plant optical housing such as a repeater or branching unit.
The UQJ (Universal Quick Joint) is a cable-to-cable joint for use unpowered short-haul cable systems.