The green and white wires inside an iPhone charging cable serve specific functions in the charging and data transfer process. Here's a breakdown of what each wire represents:

1. Red Wire: The red wire is the positive wire and carries the positive electrical charge [1].

2. Green Wire: The green wire is used for negative data (D-) transmission. It plays a vital role in exchanging data effectively between your iPhone and the charging device [1].

3. White Wire: The white wire is used for positive data (D+) transmission. It is crucial for proper data transfer through the USB cable [1].

4. Black Wire: While you mentioned a black wire, it's important to note that the standard iPhone charging cables do not include a black wire. The black wire you mentioned might be part of a different cable or a modification made to the cable [2].

Learn more:

1. Inside the iPhone charging cable there are 4 wires (red, green ...
2. Why does my iPhone charger only have red, green, and white? - Apple 30-pin to USB Cable - iFixit
3. iPhone Cable Wires Green, White, Red, Orange Explained