WhatCable: Know what your USB-C cable can do
Untangling the perplexing world of USB-C cables, WhatCable is a macOS app that diagnoses cable capabilities for speed, power, and display. It offers plain English explanations of bottlenecks based on actual negotiated performance, not just manufacturer claims. This tool resonates with HN's audience by solving a common, frustrating tech problem with transparency and technical detail.
The Lowdown
WhatCable is a macOS menu bar utility designed to demystify USB-C cable capabilities. It provides clear, actionable insights into a cable's true performance, moving beyond advertised specifications to report what your Mac actually negotiates.
- The application identifies the speed, power delivery, and display path capabilities of connected USB-C cables, pinpointing any bottlenecks in the entire connection chain (port, cable, charger, device).
- It reads the cable's e-marker identity and compares it with actual negotiated performance, offering verdicts in plain English for charging, data speed, and display resolution issues.
- Features include detecting mid-session faults, decoding e-marker data, identifying active transports (USB2, USB3, USB4, Thunderbolt, DisplayPort), and an 'Engineer mode' for raw IOKit properties.
- A command-line interface (CLI) is also provided for quick checks, scripting, and live monitoring.
- WhatCable includes 'trust signals' that flag unusual e-marker data, helping identify potentially non-compliant or suspicious cables without making definitive 'fake' declarations.
- The free version is open source, with an optional 'Pro' upgrade offering advanced diagnostics like cable history, live power metering, and negotiation diagnostics.
- It is built for Apple Silicon Macs (macOS 14+), with no support for Intel Macs due to hardware-level data availability. It emphasizes user privacy with no telemetry or background uploads.
By translating low-level hardware data into understandable insights, WhatCable empowers users to understand why their USB-C setups behave the way they do, helping them avoid frustrations with inconsistent cable performance.
The Gossip
Platform Parity Pursuits
A dominant theme in the comments is the desire for a WhatCable equivalent on operating systems other than macOS, specifically Windows and Linux. Several users expressed immediate interest in a cross-platform solution for diagnosing USB-C cable issues. While a `whatcable-linux` project is noted as an independent, related effort, some users observe that Windows may not expose the necessary low-level hardware information for such a utility to function similarly.