USB-C ใช้ได้จริงหรือไม่? ความจริงเรื่องความเข้ากันได้

## The Promise vs Reality

USB-C was supposed to be the one connector to rule them all. The connector succeeded — it's on phones, laptops, tablets, and even cars. But the **capabilities** behind that connector vary wildly.

## Same Port, Different Abilities

A USB-C port might support:
- USB 2.0 (480 Mbps) — many phones
- USB 3.2 Gen 1 (5 Gbps) — most laptops
- USB 3.2 Gen 2 (10 Gbps) — high-end laptops
- USB4 (40 Gbps)
- Thunderbolt 4 (40 Gbps + PCIe + DP)
- DisplayPort Alt Mode (video output)
- USB Power Delivery (charging 20-240W)
- Or just charging and nothing else

## The Cable Problem

USB-C cables also vary:
- A $3 charging cable might only support USB 2.0 data
- A Thunderbolt 4 cable costs $30+ but supports everything
- E-marker chips inside the cable determine power delivery limits

## How to Know What You Have

1. Check your device specs (not just "USB-C" — what standard?)
2. Look for Thunderbolt lightning bolt logo on ports
3. Check cable packaging for speed/power ratings
4. When in doubt, buy a USB4 or Thunderbolt 4 certified cable