USB-C cables, Thunderbolt, and the deep weeds of port diagnostics.
How to tell if a USB-C cable is Thunderbolt You can't tell by looking. Not reliably. The cable knows what it is. There's a chip inside the connector called an e-marker that declares its capabilities, and your Mac can read that declaration. The trick is getting it back out in a form you can use. Three ways to do it, worst to best. Method 1: look at the connector (mostly useless) Every guide on the…
Every review of WhatCable lands on the same caveat. Some cables lie about what they can do, so an app that reads a cable can be fooled. That's true. It's also half the story, and the other half is the part that makes WhatCable worth having. Here's the distinction. What a cable claims vs what the link actually does A USB-C cable with an e-marker chip carries a small block of self-description. Rated…
In macOS Tahoe 26.4, Apple added a "Slow Charger" label. Plug in a charger that can't deliver full power and the menu bar tells you so. What it doesn't tell you is why. That's the gap. The OS confirms what you already suspected (yes, it's charging slowly) and then leaves you to guess whether the problem is the adapter, the cable, the port, the battery, or the laptop itself. Most of the time it's…
USB-C is the shape of the connector. Thunderbolt is one of several high-speed protocols that uses that shape. That sentence is the entire answer to the headline question, and every page that ranks for this query opens with some version of it. The reason it keeps getting asked is that the visual is identical. A Thunderbolt 4 port and a basic USB-C 2.0 port look the same. The cables look the same.…
Welcome to the WhatCable blog. This is where I'll write about the messy, fun world underneath USB-C: why your fast cable charges slowly, what a Thunderbolt 5 cable actually negotiates with your Mac, which e-marker fields are honest and which are theatre, and the odd counterfeit or quirk that turns up in cable reports. What you'll find here A few rough buckets: Releases : what shipped in the latest…