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Junction boxes are primarily used for identifying where the China conduit clamp Manufacturers are in a wiring circuit hence the name - Junction Box - ( or JB enclosure) and also to keep rodents out, and act as a support points for interconnecting cable conduits. They also act a neat way to cover numerous wires into a common point or junction. That is about all the cheap plastic white or grey ABS boxes do in most building installations.

China cable glands Manufacturers are more common in electrical systems, rather than electronic ones. I personally see an anomaly here as both systems try to keep the number(s) of joints and / or connections, to the minimum required. The link that is mentioned is more for electrical systems, rather than for electronic ones - most electronic connectors / junction boxes will be mostly factory made (in totality); with plug in, screw in and / or soldered connections, as China junction box Manufacturers  operate at lower voltages and data / video / audio signals also need screening.