# WhatCable — macOS Menu Bar App That Identifies USB-C Cable Capabilities

> Open-source macOS menu bar utility that tells you in plain English what each USB-C cable plugged into your Mac can actually do.

## Install

Save in your project root:

# WhatCable — macOS Menu Bar App That Identifies USB-C Cable Capabilities

## Quick Use
```bash
# Install via Homebrew
brew install --cask whatcable

# Or download the .dmg from GitHub Releases
# Launch WhatCable — it appears in your menu bar
```

## Introduction
WhatCable is an open-source macOS menu bar app that reads USB-C cable metadata through IOKit and displays, in plain language, what each connected cable supports — data speed, charging wattage, video output, and Thunderbolt compatibility. It solves the universal frustration of not knowing which USB-C cable does what.

## What WhatCable Does
- Detects all USB-C cables currently connected to your Mac
- Reports maximum data transfer speed (USB 2.0, 3.x, 4.0, Thunderbolt)
- Shows maximum power delivery wattage the cable supports
- Indicates video output capability (DisplayPort Alt Mode, Thunderbolt)
- Presents all information in a clean, human-readable menu bar popover

## Architecture Overview
WhatCable is a native SwiftUI macOS app that queries the IOKit framework to read USB Power Delivery and Billboard BOS descriptors from connected cables. It maps raw USB descriptor fields to human-readable capabilities using Apple's IOUSBHostDevice APIs. The app runs as a lightweight menu bar agent with minimal memory and CPU footprint, polling for cable changes on connect/disconnect events.

## Self-Hosting & Configuration
- Install via Homebrew Cask or download from GitHub Releases
- Requires macOS 13 Ventura or later
- No configuration needed — launches as a menu bar icon automatically
- Optionally set to launch at login via System Settings
- Works on both Intel and Apple Silicon Macs

## Key Features
- Instant identification of USB-C cable specs without any manual lookup
- Native SwiftUI interface that matches macOS design language
- Zero configuration — plug in a cable and read the result
- Lightweight menu bar agent with negligible resource usage
- Open-source with no telemetry or network access required

## Comparison with Similar Tools
- **System Information (macOS)** — shows USB devices but not cable-specific capabilities; WhatCable focuses on cable specs
- **USB Prober** — Apple developer tool for raw USB descriptors; WhatCable translates these into plain English
- **USBDeview (Windows)** — Windows USB device viewer; WhatCable is macOS-native and cable-focused
- **Cable labeling** — physical labels fade or are absent; WhatCable provides instant digital identification
- **Thunderbolt Accessories** — macOS settings panel shows Thunderbolt devices but not cable wattage or USB details

## FAQ
**Q: Does WhatCable work with all USB-C cables?**
A: It works with cables that expose USB PD and Billboard descriptors. Very cheap cables with no electronic marker chip may show limited information.

**Q: Can it detect cable length or brand?**
A: No, cable length and brand are not stored in USB descriptors. WhatCable reports electrical capabilities only.

**Q: Does it work with USB-C to USB-A adapters?**
A: It detects the adapter as a connected device but cable-specific metadata depends on the adapter's descriptor support.

**Q: Is there a Windows or Linux version?**
A: No, WhatCable is macOS-only, built on Apple's IOKit framework.

## Sources
- https://github.com/darrylmorley/whatcable

---
Source: https://tokrepo.com/en/workflows/asset-c3fe2a04
Author: AI Open Source