Modular Connectors
Although originally designed for telephone usage and later adopted for computer networking, the Modular connector has been used for microphone connections extensively on modern amateur radio equipment, including models from the three major manufacturers (Icom, Kenwood, and Yaesu), but primarily used on mobile radio equipment (designed to be mounted in vehicles).
Like the screw-on round microphone connectors, there is little standardization among manufacturers, and even among different models from the same manufacturer, leading to significant interoperability problems when connecting non-OEM or homebrew microphones and other equipment.
Most radios with modular microphone connectors use the 8P8C (vernacular: RJ45) connector, but some use 6P6C or 4P4C connectors.
Read more about this topic: Microphone Connector