question: Why aren't charger/data ports in phones shaped more like a headphone jack?
comment: Headphone jacks aren't really a great design, but they usually work OK if you only have a small number of signals. If you want to use a bunch of signals, making sure that each of them has a solid connection can get tricky. It's just not a great system from a mechanical point of view, and that can result in cruddy electrical connections. Particularly as things wear out. It could also create more problems with crosstalk (interference). With a typical data port, you can keep signal wires from crossing. That gets a little difficult at the end of a round jack if there are a lot of signals. It also gets a little more tricky to keep the signal wires the same length, which is valuable with high speed signals.
passages: Using the connector may require a breakout cable or special headset. Most often, the user must buy a special adapter or pigtail to make the correct connections to a 2.5mm TRS connector for a monophonic headset or 3.5mm 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.
   BULLET::::- Some devices transparently handle many jack standards, and there are hardware implementations of this available as components.
  
  BULLET::::- The Android Wired Audio Headset Specification requires the CTIA pinout order (LRGM), "Except in regions with legal requirements for OMTP pinout". This document also describes the headset button actions, and these may be taken from the CTIA spec.
  
  BULLET::::- The USB Type-C Cable and Connector Specification Revision 1.1 specifies a mapping from a USB-C jack to a 4-pole TRRS jack, for the use of headsets, and supports both CTIA and OMTP (YD/T 1885-2009) modes. See Audio Adapter Accessory Mode (Appendix A).
   Some manufacturers now offer USB magnetic port adapters; as of 2018 all product are proprietary incompatible designs. Magnetic connectors were developed mainly for mobile phones devices having Micro B, USB-C or Apple's Lightning ports. They offer ease of operation and are also intended to protect the mobile device's connector from deteriorating under the mechanical action of connecting and disconnecting. 
  
  Section::::Cabling.
   The charger/headset jack for the F3 Motofone (and variants) was not a standard 2.5 mm or 3.5 mm headset port. It was a DC connector that can support mono sound quality. This is not well documented at Motorola, and internal documentation indicates the jack is a standard 2.5 mm TRS connector jack. The jack shown on the Motorola site clearly has a pin in the center of the jack, prohibiting use of a standard 2.5 mm plug. A mono headset was available as part number CFLN6103AA and the name of it is Motorola S215 Pedestrian Kit. This is a headset only and not an adapter.
   Manufacturers of personal electronic devices might not include a USB standard connector on their product for technical or marketing reasons. Some manufacturers provide proprietary cables that permit their devices to physically connect to a USB standard port. Full functionality of proprietary ports and cables with USB standard ports is not assured; for example, some devices only use the USB connection for battery charging and do not implement any data transfer functions.
   The port also connects wired headsets or speakers, etc.
  
  Section::::Location.
  
  Originally, the FastPort was placed on the bottom edge of the phone (when viewed from the front), for a while on the top edge, and finally on the left edge. These changes caused some accessories to become unusable, such as holders with charging options and docks.
  
  Section::::Layout.
   When connecting two DTE devices such as a computer and a printer, the Digital BC16E crossover cable is used.
  
  Thrustmaster is also using the MMJ connector for connecting its line of rudder pedals and racing pedals to either USB via a proprietary Thrustmaster Adapter, or directly to a joystick or racing wheel. 
  
  The more recent Lego Mindstorms sets, beginning with the NXT, used similar plugs for motors and sensors to prevent phone lines being plugged in. 
   BULLET::::- Some wireless carriers (most notably Verizon Wireless) require that handset manufacturers limit the sideload capabilities of devices on their networks as a form of vendor lock-in. This usually results in the loss of USB and Bluetooth as sideload options (though memory card transfer is still available).
  
  Section::::Methods.
  
  Section::::Methods.:USB sideloading.
  
  Sideloading over a USB connection was standardized by OMTP in late 2007. Until this time, mobile phone manufacturers had tended to adopt proprietary USB transfer solutions requiring the use of bundled or third party cables and software.
   , all new mobile phones applying for a license in China are required to use a USB port as a power port for battery charging. This was the first standard to use the convention of shorting D+ and D−.
  
  Section::::Mobile device charger standards.:OMTP/GSMA Universal Charging Solution.
  
  In September 2007, the Open Mobile Terminal Platform group (a forum of mobile network operators and manufacturers such as Nokia, Samsung, Motorola, Sony Ericsson, and LG) announced that its members had agreed on Micro-USB as the future common connector for mobile devices.
   Prior to Power Delivery, mobile phone vendors used custom protocols to exceed the 7.5 W cap on USB-BCS. For example, Qualcomm's Quick Charge 2.0 is able to deliver 18 W at a higher voltage, and VOOC delivers 20 W at the normal 5 V. Some of these technologies, such as Quick Charge 4, eventually become compatible with USB PD again.
  
  Section::::Power.:Sleep-and-charge ports.
   Additionally, many devices have USB On-The-Go and support USB storage, in most cases using either a special USB micro-B flash drive or an adapter for a standard USB port. Such adapters can also be used with various other USB devices, such as hardware mice and keyboards.
  
  Section::::Chargers and external batteries.
  
  Smartphone chargers have gone through a diverse evolution that has included cradles, plug-in cords and obscure connectors. However, more recent devices generally use micro-USB. (Apple devices still use proprietary cables, though the form-factor of their 30-pin plug used on older devices has shown up elsewhere.
   , all new mobile phones applying for a license in China are required to use a USB port as a power port for battery charging. This was the first standard to use the convention of shorting D+ and D− in the charger.
  
  Section::::Power.:Mobile device charger standards.:OMTP/GSMA Universal Charging Solution.
  
  In September 2007, the Open Mobile Terminal Platform group (a forum of mobile network operators and manufacturers such as Nokia, Samsung, Motorola, Sony Ericsson, and LG) announced that its members had agreed on Micro-USB as the future common connector for mobile devices.
   BULLET::::- Moog synthesizers and plug modifiable synthesizers.
  
  BULLET::::- LCD monitors with built-in speakers will need a cable with 3.5 mm male TRS plugs on each end to connect to the sound card.
  
  BULLET::::- Note: Some higher-end sound cards provide a breakout panel which supports  in plug devices as well.
   Some newer computers, such as Lenovo laptops, have 3.5 mm TRRS headset sockets, which are compatible with phone headsets and may be distinguished by a headset icon instead of the usual headphones or microphone icons. These are particularly used for Voice over IP.
  
  Section::::Video.
  
  Equipment requiring video with stereo audio input/output sometimes uses 3.5 mm TRRS connectors. Two incompatible variants exist, of and length, and using the wrong variant may either simply not work, or could cause physical damage.
   The port can charge the battery and power the phone while it is connected to, for example, a hands-free solution in a car. The FastPort became the only way to get external power to the phones. Chargers comes in several varieties, from 12/24 volt DC to use in cars, to 100-250 volt AC to use elsewhere. Some charger-models can only charge the phone (the cable is attached at the middle), in others all the connector pins through to the plug end, thus supporting data/signal transfer while the phone is being charged.
  
  Section::::Functions.:Sound accessories and headsets.
   The 3.5mm TRRS connector for the headphones is located on the top left corner of the device for the first five generations (original through 4S), after which time it was moved to the bottom left corner. The headphone socket on the first-generation iPhone is recessed into the casing, making it incompatible with most headsets without the use of an adapter. Subsequent generations eliminated the problem by using a flush-mounted headphone socket. Cars equipped with an auxiliary jack allow handsfree use of the iPhone while driving as a substitute for Bluetooth. The iPhone 7 and later have no 3.5mm headphone jack, and instead headsets must connect to the iPhone by Bluetooth, use Apple's Lightning port (which has replaced the 3.5mm headphone jack), or (for traditional headsets) use the Lightning to 3.5mm headphone jack adapter, which is included with iPhone 7 up until iPhone X and plugs into the Lightning port.
   Section::::Aviation and US military connectors.
  
  US military phone connectors include both 0.25 in (6.35 mm) and 0.21 in (5.34 mm) diameter plugs, which both mate with the M641-series open frame jacks, exemplified by Switchcraft C11 and C12 jacks.
  
  Military specifications and standards relating to phone connectors include MIL-STD 202, MIL-P-642/*, and MIL-J-641.
  
  Section::::Aviation and US military connectors.:Headphones.
   Section::::Implementations.
   Some manufacturers offered panel-mounted jacks with potential-free auxiliary contacts that would open if a plug were inserted.
  
  Section::::Loudspeaker connector.
   BULLET::::- Automotive interfaces for charging mobile devices: cigar lighter receptacle and USB respectively had 12 volt and 5 volt systems. The 5 volt system derived from data buses for PCs whereas the 12 volt system derived from the automobile's native electrical system. The popularity of car chargers for cell phones is what later led to this movement, and later on newer models of automobiles were equipped with both (sometimes USB on the car radio faceplate).
  
  Section::::2010s.
   On the other hand, when a passive set of USB-C headphones or adapter is used, analog audio is sent through the USB-C port. The conversion by the DAC and amplifier is done on the phone; the headphones or adapter simply passthrough the signal. The sound quality is dependent on the phone's onboard DAC. Passive adapters without a built-in DAC are only compatible with devices that output analog audio, adhering to the Audio Adapter Accessory Mode specification.
  
  Section::::Hardware support.:Compatibility issues.:Compatibility with other fast charging technology.
   In the Bell System, following the Communications Act of 1934, the telephone companies owned all telecommunications equipment and they did not allow interconnection of third-party equipment. Telephones were generally hardwired, but may have been installed with Bell System connectors to permit portability. The legal case "Hush-A-Phone v. United States" (1956) and the Federal Communications Commission's (FCC) "Carterfone" (1968) decision brought changes to this policy, and required the Bell System to allow some interconnection, culminating in the development of registered interfaces using new types of miniature connectors.
   BULLET::::- Microphone input (mono, usually with 5 V power available on the ring. Note that traditional, incompatible, use of a stereo plug for a mono microphone is for balanced output)
  
  BULLET::::- Older laptop computers generally have one jack for headphones and one mono jack for a microphone at microphone level. An attenuating cable can be used to convert line level or use a signal from an XLR connector, but is not designed to record from a stereo device such as a radio or music player. Newer computers may feature a single TRRS female jack (see below).
   The European Union defined a Common external power supply for "hand-held data-enabled mobile phones" (smartphones) sold from 2010, intended to replace the many incompatible proprietary power supplies and eliminate waste by reducing the total number of supplies manufactured. Conformant supplies deliver 5 VDC via a micro-USB connector, with preferred input voltage handled ranging from 90 to 264 VAC.
  
  In 2006 Larry Page, a founder of Google, proposed a and up to standard for almost all equipment requiring an external converter, with new buildings fitted with wiring, making external AC-to-DC adapter circuitry unnecessary.
   Before a universal charger standard was agreed upon in the late 2000s users needed an adaptor which was often the same brand, which each had their own interface, as their phone to recharge the battery. Since then mobile phones from major brands typically use a USB cable with a micro-USB or, since the mid-2010s, USB-C interface. Apple's iPhone is the sole major brand to retain its own interface (30 dock connector replaced by Lightning in 2012).
  
  Section::::Mobile device charger standards.:In China.
  