With the launch of the iPhone 5, many users found that the Earpods headset of the Bank of China iPhone 5 can be used on the original device, but cannot be used on other PCs or even the Hong Kong version of the iPhone 5. At the beginning, many consumers wondered whether there was a problem with the quality of the earphones, or whether the original earphones were swapped. In fact, this was not the case. The reason for this was just the different earphone standards.

At present, there are two universal mobile phone headset interface standards in the world, one is the OMTP standard and the other is the CTIA standard. Generally speaking, most international manufacturers use the CTIA standard, such as iPhone headsets in the United States, Hong Kong and other international markets, while domestic products need to support the OMTP standard. Here is a brief introduction:

① 3.5 mm interface of international standard (CTIA): The pin connection is left channel right channel ground wire microphone. It is also the most popular and widely used connection in the market. CTIA headsets are applicable to mobile phones: Apple (full series), Xiaomi (full series), Meizu (full series), Sony (full series), LG (full series), official HTC products, Samsung (customer service consulting), some Motorola models (ME865), Lenovo W101, Nokia Lumia and WP7 series, Huawei (C8812/U9200), Yitong T900, etc

② 3.5 mm interface of national standard (OMTP): The pin connection is left channel - right channel - microphone - ground wire. Mobile phone range: Nokia, Sony Ericsson (full range), ZTE (full range), Bubugao (full range), Coolpad (full range), HTC unofficial products (A3380 A3360、T9188、A9188、Z510D）、 Samsung old products (i8910 M3510C、M7500、F278、F700、F408、F490、G810、G818、G818E、i550W、8510、i560、S8000C、i8000、M2710C、i7500U、i9000、i6500U、F809、i8000、F859）、 Motorola XT531, Lenovo A520/A750/P700, OPPO (full series) and other domestic mobile phones.

Since the design methods of CTIA and OMTP are not the same, there must be a problem in cross use. If the CTIA headset is connected to the non international standard (OMTP) interface, only the background sound will appear. Press and hold the call button on the microphone to display the voice normally.

In order to adapt to China's national conditions, Apple China has made a series of modifications to the Earpods earphones launched in the Chinese market to make them meet the domestic OMTP standard. Therefore, the original iPhone 5 earphones of the Bank of China are actually different from Earpods earphones issued in other regions, and the standards supported are different, so it is not surprising that there are problems with serial use.

Of course, there is no way to solve the problem that CTIA and OMTP standards are different. The above figure shows a commercially available headphone conversion cable called FiiO LU2, which can enable the interoperability of headphones of different standards. Use it to transfer the headset, and the problem can be solved. However, considering that a few users have high requirements for sound quality, and this kind of conversion line may cause slight loss in sound quality, it is necessary to consider clearly when purchasing.

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