Although the classification of connector product types is somewhat confusing, technically speaking, there are only two basic ways to classify connector product categories:
① According to the external structure: circular and rectangular (cross-section);
② By operating frequency: low frequency and high frequency (with 3MHz as the boundary).
According to the above classification, coaxial connectors belong to circles, printed circuit connectors belong to rectangles (historically, printed circuit connectors have indeed been separated from rectangular connectors to form their own category), and the currently popular rectangular connectors have a trapezoidal cross-section, similar to a rectangle. The frequency division of low and high frequencies based on 3MHz is also basically the same as that of radio waves.
As for other types that can be classified according to their purpose, installation method, special structure, special performance, etc., they often appear in publications and manufacturers' promotional materials, but generally only to highlight a certain feature and purpose, and the basic classification still does not exceed the above classification principles.
Considering the technological development and practical situation of connectors, connectors can be classified into the following categories (subcategories) based on their universality and relevant technical standards:
① Low frequency circular connector;
② Rectangular connector;
③ Printed circuit connectors;
④ RF coaxial connector;
⑤ Fiber optic connectors.
