An enhanced mini-USB (EMU) connector is a type of hybrid electrical connector which carries

Universal Serial Bus Universal Serial Bus (USB) is an industry standard that establishes specifications for cables, connectors and protocols for connection, communication and power supply (interfacing) between computers, peripherals and other computers. A broad ...

data and power as well as other connections such as bidirectional audio. It was invented for and is mainly used on

mobile phone A mobile phone, cellular phone, cell phone, cellphone, handphone, hand phone or pocket phone, sometimes shortened to simply mobile, cell, or just phone, is a portable telephone that can make and receive calls over a radio frequency link whi ...

Motorola Motorola, Inc. () was an American multinational telecommunications company based in Schaumburg, Illinois, United States. After having lost $4.3 billion from 2007 to 2009, the company split into two independent public companies, Motorol ...

HTC Corporation HTC Corporation ( zh, t=宏達國際電子股份有限公司, s=宏达国际电子股份有限公司, p=Hóngdá Guójì Diànzǐ Gǔfèn Yǒuxiàn Gōngsī, first=t) or High Tech Computer Corporation, (literally ''Hongda International Electron ...

, and other mobile phone manufacturers use EMU connectors.HTC Hermes USB connector pin config
/ref> There is more than one standard for EMU connectors, which are incompatible between manufacturers, but all are physically and electrically compatible with standard mini-USB connectors. The EMU connector has five pins for USB on one side. While regular USB connectors are empty on the other side, EMU has more pins intended for headsets. In HTC's version, two pins are for the microphone, three are for stereo sound, and one is for the

push-to-talk Push-to-talk (PTT), also known as press-to-transmit, is a method of having conversations or talking on half-duplex communication lines, including two-way radio, using a momentary button to switch from voice reception mode to transmit mode. H ...

switch. In the CEA-936-A standard, there are no extra pins — the USB data pins are also used for

RS-232 In telecommunications, RS-232 or Recommended Standard 232 is a standard originally introduced in 1960 for serial communication transmission of data. It formally defines signals connecting between a ''DTE'' (''data terminal equipment'') such ...

transmit and receive, stereo audio left and right, or for microphone and speaker/earpiece. Devices select which function the pins perform depending on user settings or on the context or mode in which the device is being operated. Two different functions cannot be used at once. Using the connector may require a breakout cable or special headset. Most often, the user must buy a special adapter or

pigtail A woman with long pigtails and braids. In the context of hairstyles, the usage of the term pigtail (or twin tail or twintail) shows considerable variation. The term may refer to a single braid, but is more frequently used in the plural ("pi ...

to make the correct connections to a 2.5 mm

TRS connector A phone connector, also known as phone jack, audio jack, headphone jack or jack plug, is a family of electrical connectors typically used for analog audio signals. A plug, the male connector, is inserted into the jack, the female connecto ...

for a monophonic headset or 3.5 mm for stereo headphones. True breakout cables which provide all connections are unavailable, thus a phone cannot be charged at the same time as a headset or headphones are inserted, even for EMUs with extra pins. Some mobile phone companies have used the extra pin "X" to enforce the use of their own battery chargers.

Verizon Wireless Verizon is an American wireless network operator that previously operated as a separate division of Verizon Communications under the name Verizon Wireless. In a 2019 reorganization, Verizon moved the wireless products and services into the div ...

is the first company to require first-party battery chargers, having colluded with Motorola to put an arbitrary 1.4 volts on pin X. This voltage violates the

USB-IF The USB Implementers Forum (USB-IF) is a nonprofit organization created to promote and support USB (Universal Serial Bus). Its main activities are the promotion and marketing of USB, Wireless USB, USB On-The-Go, and the maintenance of the sp ...

standards, as pin X should either be tied to ground or not connected at all. Without this connection, the phone will refuse to charge, displaying "unauthorized charger" despite receiving the proper current. The phone will charge while connected to a personal computer only if the PC is running a special device driver. Extra pins in hybrid mini-USB connectors are used as non-standard compliant way to provide USB 3.0 SuperSpeed connectivity as alternative to standard SuperSpeed micro-B and

USB-C USB-C (properly known as USB Type-C) is a 24-pin USB connector system with a rotationally symmetrical connector. The designation C refers only to the connector's physical configuration or form factor and should not be confused with the conn ...

connectors.

References

External links

* {{USB USB Electrical connectors