1. Why Old Phone Chargers Did Not Fit: Each Maker Had Its Own Charging Specs Before 2004
Many homes have old mobile phone chargers tucked away in the back of a drawer. You might try to plug one into a current smartphone, but the shape does not fit. According to technical explanations from NTT Docomo, before 2004, each manufacturer designed its own unique charging specifications. [1]
For FOMA devices from 2004 onwards, the charging specifications were unified, and AC adapters were standardized. [1] This explanation refers specifically to Docomo. It does not mean that all mobile phones in Japan were standardized at that exact moment. [1]
The "AC adapter" mentioned here is a component that changes the alternating current from the wall outlet into direct current suitable for the device. Most items called "chargers" contain this component. [1]
2. The 2009 Pledge by Phone Makers and Operators to Standardize Chargers
In February 2009, the GSMA (an association of global mobile operators) and 17 mobile manufacturers and telecom operators announced a policy to standardize mobile phone chargers by 2012. They planned to use Micro-USB and aimed to reduce power consumption during standby. [2]
In October of the same year, the ITU, a United Nations agency, approved a "Universal Charging Solution" based on Micro-USB (Recommendation ITU-T L.1000). This solution aimed to ensure the same charger could be used for future models and required an efficiency rating of four stars or higher. [3]
Neither of these were laws. They were voluntary industry pledges and international recommendations. Also, the current version of L.1000 from July 2019 may not be identical to the original content from 2009. [3]
3. Apple's Lightning (2012) and USB Type-C (2014): Ports That Plug In Either Way Up
On September 12, 2012, Apple announced the Lightning connector along with the iPhone 5. It replaced the previous 30-pin dock connector with an 8-pin terminal that can be plugged in either way. [4] However, Lightning is Apple's proprietary standard, not USB. [4]
On August 11, 2014, the USB Type-C specification 1.0 was released by USB-IF (the organization that defines USB specifications). It has 24 pins and can also be plugged in either way. [5]
By 2012, the year targeted by the 2009 standardization pledge, a different type of terminal had already appeared outside the industry agreement. [5]
4. Why USB-C Cables With the Same Shape Can Differ Inside
Imagine the inside of a USB-C cable like a water hose. Even if the nozzle shape is the same, the amount of water that can flow at once changes depending on whether the tube inside is thick or thin. In reality, this is electricity, and the differences are in voltage, current, and the number of wires. [5]
According to USB-IF materials, standard cables support up to 3A and 20V (maximum 60W). Traditional 5A and 20V cables can send up to 100W. Furthermore, in the Extended Power Range (EPR) of USB PD 3.1, the standard envisions raising the voltage to a maximum of 48V while keeping 5A, allowing up to 240W. [6]
The 100W figure applies at 20V. In the EPR mode, raising the voltage allows the power to reach a maximum of 240W. 240W is four times 60W, and 100W is about 1.7 times 60W. [6]
There are also differences in communication. Type-C cables for USB 2.0 have fewer wires and can only handle USB 2.0 communication and power delivery. [5] Many cables contain an e-Marker chip that tells the device the cable's capabilities. [5]
240W is strictly a maximum value. Your specific cable and charger may not be able to deliver that much power. [6]
5. Why the EU Made USB-C Charging Ports Mandatory
Through Directive 2022/2380, the EU made USB-C charging ports mandatory for devices such as mobile phones, tablets, digital cameras, headphones, and handheld game consoles placed on the EU market on or after December 28, 2024. Laptops are included starting April 28, 2026. [7]
The communication method for fast charging (USB PD) must also be aligned. However, this does not mean all chargers will charge at the same speed. Users can choose whether to buy a device with or without a charger, and charging features must be displayed on the box. [7] By December 2026, the European Commission will report on the impact of selling chargers separately. Selling chargers separately is not mandatory. [7]
One reason for this move is electronic waste and cost. Estimates from the European Parliament suggest that mobile phone chargers create about 11,000 tons of e-waste annually, and purchasing unnecessary chargers could be reduced by up to 250 million euros per year. [8] "Up to" means this is a maximum estimate. [8]
In the context of this move, the iPhone 15 and iPhone 15 Plus, released in 2023, became the first iPhones with USB-C. Compliance with EU rules was cited as a background factor. By February 2025, all iPhones on sale had USB-C. [4]
This applies to the EU market. Whether Japan has the same rules is not covered in this article. [7]
6. How to Compare the Cables in Your Home by Port Shape
Line up the cables in your home and count how many different port shapes there are. Just look at them; do not plug them into devices or unplug them. [5]
Next, look for small text on the chargers. You might see numbers followed by "W". Many cables do not have text, so it is okay if you cannot find any. If a charger or cable seems unusually hot, tell an adult and do not touch it. [6]
If you have old devices in a drawer, compare their port shapes with your current ones. You can verify the story in this article with your own eyes. [1]
To read the original sources, power information for USB-C is on the USB-IF page (in English), and EU rules are summarized on the European Parliament website (in English). [7]