Although the classification of connector product types is somewhat confusing, technically speaking, there are only two basic classifications for connector product categories:
Classification method: ① According to the external structure; Circles and rectangles (cross-section), ② according to operating frequency; Low frequency and high frequency (bounded by 3MHz)
According to the above division, 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), while popular rectangular connectors have a trapezoidal cross-section, similar to rectangles. The frequency division of low-frequency and high-frequency and radio waves is also basically the same with a 3MHz boundary
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 manufacturer's promotional materials. However, they are generally only used to highlight a certain feature and purpose, and the basic classification still does not exceed the above classification principles
Considering the technological development and actual situation of connectors, based on their universality and relevant technical standards, connectors can be divided into the following categories (sub categories): ① Low frequency circular connector; ② Rectangular connector; ③ Printed circuit connectors; ④ RF connector; ⑤ Fiber optic connectors