1. Physical Structure of MMCX Interface

The MMCX interface consists of a plug and a socket. The plug includes a central contact (inner pin) and an outer shell, while the socket includes a central socket (inner hole) and an outer shell. In the MMCX interface, the central contact or socket is usually defined as the signal line, which we commonly refer to as the "positive pole"; the outer shell is usually defined as the ground wire, i.e., the "negative pole".

2. Electrical Characteristics of MMCX Interface

In terms of electrical connection, the polarity of the MMCX interface can also be determined by measuring the voltage. Generally, the voltage of the positive pole is higher than that of the negative pole. Therefore, the polarity of the MMCX interface can be determined with a voltmeter.

However, it's important to note that the polarity of the MMCX interface, whether viewed from its physical structure or electrical characteristics, is not as distinct as that of a DC power source. This is because the MMCX interface transmits radio frequency signals, which operate differently from DC power sources. Therefore, in practical applications, the physical structure of the MMCX interface is often referenced to determine "polarity".

In summary, the polarity determination of the MMCX interface mainly depends on its physical structure, with the central contact or socket serving as the "positive pole" and the outer shell as the "negative pole". In actual applications, users need to make detailed judgments and operations based on the specific device's interface definition and user manual to ensure correct connection and normal operation of the device.