Why is the line control not compatible with the mystery of the 3.5mm cheap signal connector headphone jack?

Why is the line control not compatible with the mystery of the 3.5mm cheap signal connector headphone jack?

2019-01-28 10:39:43

      

At present, the cheap signal connector headphone interface we use is a big family. The common three-stage interface is called TRS terminal, the four-stage type is TRRS terminal, T is the abbreviation of "tip", and R is "ring", S It is "sleeve", the most applications of 2.5mm, 3.5mm and 6.35mm, the most original 6.35mm caliber has been applied since 1878, has been 130 years old, the earphone interface uses metal plus insulation ring The column design has been around for a long time and can be said to be quite mature.

Why is the line control not compatible with the mystery of the 3.5mm headphone jack?

Since the interface is so mature, is the reason for the incompatibility really caused by the interface? In fact, for headphones with 3.5mm TRRS terminals, some problems are still on the interface. Although the shape of the interface is standardized, there is no specific specification for the function definition of each segment of the interface. To understand the incompatible source. It seems that more in-depth research is needed.

There are big mysteries in simplicity. Four-headed earphone plugs are two standard.

Why is the line control not compatible with the mystery of the 3.5mm headphone jack?

Why is the line control not compatible with the mystery of the 3.5mm headphone jack?

RRS terminal two standards have different definitions of interface functions

The 3.5mm TRRS terminal used in smartphones has two interface definition standards, OMTP and CTIA. OMTP is our common national standard. CTIA is an international standard. The definitions of the two standards are the same in the first two sections of the interface. From top to bottom, the positives of the left and right channels are the same, but the definitions of the latter two are different. OMTP adopts the design of the positive and negative grounding of the line microphone, while the CTIA is just the opposite, first ground and then the microphone, I believe you netizens. Everyone knows that to make the circuit conductive, it must be made into a loop. If the earphone interface of the mobile phone adopts the OMTP standard, the earphone inserted into the CTIA standard must not form a loop, which is why there is no earphone on the mobile phone.

Why is the line control not compatible with the mystery of the 3.5mm headphone jack?

Let's take a look back at the definition of the three-stage TRS terminal, from left to right, left channel, right channel and ground, which is why it is compatible with any mobile phone.

In fact, to solve the incompatibility between OMTP and CTIA is also very simple, as long as the grounding and microphone positive exchange can be used, as long as you search online, you will find that the OMTP, CTIA adapter plugs are still quite a lot of businesses. And the price is not expensive, if you encounter this situation around you may wish to choose to buy a adapter. With the continuous development of mobile phones, this kind of complete incompatibility is also decreasing. The latest mobile phones basically use the CTIA standard. In addition, it is said that mobile phones have added the OMTP/CTIA identification mechanism, and the mobile phone can automatically recognize the standard adaptive output.

 

 

The simple and simple principle The remote control structure is not mysterious.

The most incompatibility encountered is still a malfunction of the wire control. Now that we have understood the definition of the headphone interface, how is the multi-key wire control operation realized? In fact, the principle is also very simple, only the microphone is positive for the input signal on the headphone jack. Since the multi-key line control headset uses the 4-segment interface, the command of the line control must also be input into the mobile phone here.

Why is the line control not compatible with the mystery of the 3.5mm headphone jack?

There are several types of wire control commonly found in the market. The volume slider has a wheat wire control, a single button with a wheat and a multi-button with a wheat. The principle of changing the volume through the volume slider is very simple, as long as a variable resistor is inserted in the circuit. It can be achieved. The use of multiple buttons is more complicated, but it is still achieved by changing the resistance. It is easy to see from the schematic circuit diagram that different resistors are connected under different keys. When the button is pressed, different resistors are connected. In the loop, the signal received by the positive pole of the microphone also changes, so that the mobile phone can identify which button the user pressed and what operation should be performed. If there are a lot of remote control buttons, it will be more complicated. Generally, the control chip will be installed in the online control, and even the wire control using the wired carrier technology. The small series will not be elaborated here. In short, the fundamental principle is the same. Judging what the user did for the remote control is judged by the signal change of the positive input of the microphone.

Why is the line control not compatible with the mystery of the 3.5mm headphone jack?

Headphone remote control

Then the reason for the incompatibility of the line control is obvious. It is because different manufacturers have different design and definition of the line control, which causes the mobile phone to not correctly judge which input signal should be corresponding. There is no very simple and effective solution to the phenomenon of malfunction of the line control function. A small number of users with strong hands-on ability have chosen DIY to replace the line control by themselves, but the risk is very high. Xiaobian does not recommend that everyone follow suit.

Completely solve the problem of future mobile phone remote control

The main reason for the incompatibility of mobile phone headsets is that the interface definitions are different and the wire control signals cannot be correctly identified. The unsolvable solution due to different interface standards is very simple. Just buy a adapter. However, the phenomenon of line control failure is more troublesome, and it is necessary for the manufacturer to follow up in time or to develop a unified standard. As far as Xiaobian's personal experience is concerned, the situation in which the headset is not working properly is mainly focused on the volume control and playback control. The simplest answering and hangup function is still rarely inoperable. You can't determine the compatibility with the purchase of headphones. Otherwise, you can consider the one-button or resistance slider to control the volume of the headset.

The development of mobile phones is changing with each passing day. Many manufacturers will launch two new flagship products in one year. At the same time of rapid development, Xiaobian also hopes to have better progress in terms of details. I believe that the compatibility problem will be thoroughly eliminated soon. solved.
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