The 3.5mm plug is the most common for everyone, and most mobile phones and headphones are used. How many kinds of connectors are commonly used in headphones? In fact, it's not complicated at all, let's talk about it briefly today!
3.5mm TRS: The three-segment 3.5mm TRS is the most common headphone plug. From top to bottom, it is left channel, right channel and ground. It is compatible with most mobile phones and DAP.
3.5mm TRRS: Earphones with wired control function, you will find that the plug is a 4-segment TRRS. In addition to the left channel, right channel, and ground, there is also a section that can transmit radio signals.
The 3.5mm TRRS 4-segment plug can transmit left channel, right channel, ground and microphone signals.
6.3mm: The plug is a 3-segment design, with left channel, right channel and ground. Due to the large area occupied, it is generally only used on home audio equipment, such as two-channel amplifiers, big ear cows, Karaoke microphones, etc.
4-pin XLR: Appears on big ear cows or household ear amplifiers. It is a balanced plug. The positive and negative of the left and right channels are completely separated, but the grounding is shared, which can achieve balanced transmission.
The 4-pin XLR balanced output jack will only appear on home ear amplifiers.
2.5mm TRRS: Some DAPs are equipped with balanced output jacks. The amplification circuit can be processed independently on the left and right. The gain output is very sufficient, which not only makes the headphones easier to push, but also reduces the noise affected by the current, making the music more clear and beautiful. The 2.5mm TRRS balanced plug has a 4-segment structure. The positive and negative signals of the left and right channels are transmitted separately and have a ground wire.
4.4mm: The Japan Electronics and Information Technology Industry Association (JEITA) announced the headphone definition standard "RC-8141C" in March. It chose a 4.4mm 5-segment type as the balanced headphone plug standard, except for the positive and negative poles of the left and right channels. Outside, the grounding is also independent. The 4.4mm balanced plugs and jacks are currently only used by Sony audio products. Whether the new specifications can unify the current chaotic balance standards, I believe it will take another year or two to see.
For the time being, only 4.4mm balanced plugs are used in Sony audio products.
Lightning: As the name suggests, it is specially designed for iOS devices, which lacks flexibility to a certain extent. The output of the traditional 3.5mm headphone jack is an emulation signal, which needs to be decoded by the built-in DAC of the mobile phone and converted into an emulation signal before being transmitted to the earphone. However, the earphone with Lightning interface can put the DAC chip in the earphone, and the earphone manufacturer can choose the DAC decoding chip by himself to ensure that the earphone's due strength can be exerted.