WhatCable: Unveiling the Secrets of Your USB-C Cables
In the world of technology, where cables and connections are ubiquitous, it's often challenging to discern the quality and capabilities of our devices. Enter WhatCable, a free Mac app that acts as a detective, revealing the hidden truths about your USB-C cables. This innovative tool, crafted by Darryl Morley, harnesses the power of Apple's own data collection to provide an in-depth analysis of your USB-C connections.
WhatCable's magic lies in its ability to read the data your Mac gathers about connected USB devices. It accesses information that Apple doesn't typically share, such as the vendor ID, speed rating, current rating, and voltage limits. This data is then presented in an intuitive menu bar widget, offering a comprehensive view of your USB-C cables and devices.
Darryl Morley explains the process: "Every Apple Silicon Mac has a port controller chip that handles USB Power Delivery negotiation. When a cable with an e-marker is plugged in, the port controller sends a 'Discover Identity' message, and the cable responds with detailed specifications. macOS stores this response in the IOKit registry, and WhatCable reads it using Apple's public APIs."
The app's capabilities go beyond mere specifications. It also reads the Mac's hardware, including the negotiated connection speed, Thunderbolt link speed, and live voltage and current at each port. By combining this data with the device's information, WhatCable can provide real-time insights into the actual performance of your connections.
One of the most intriguing aspects of WhatCable is its ability to expose discrepancies between a cable's claimed capabilities and its actual performance. For instance, the app can reveal that a cable claiming 100W charging speeds might only deliver 60W, or that a cable labeled as 10Gbps might fall short of that speed when connected to a fast SSD.
In my testing, WhatCable proved to be a valuable tool. It helped me identify a faulty cable that was falsely claiming 100W charging capabilities, even though it only delivered 60W. Conversely, it also confirmed the performance of a high-quality cable, showing that it was indeed capable of 100W charging as advertised.
WhatCable's accuracy and utility are further emphasized by its comparison with the $8 cable tester mentioned in the source. While the tester can confirm the existence of an e-marker, it falls short in providing detailed information about the cable's actual performance, such as charging speeds.
Darryl Morley's WhatCable is not the first of its kind. A similar app, USB Connection Information, was released a year ago. However, WhatCable stands out for its free nature and Morley's commitment to keeping it that way. The Pro version, available for £9.99, adds real-time power monitoring, diagnostics, and a terminal view.
Morley's vision extends beyond WhatCable. He has also developed WhatPort, a simpler app that monitors the activity of each USB-C port on your Mac, including power, data, and video. Unfortunately, WhatCable is currently limited to Mac users, as Morley faces challenges in building a Windows version due to hardware variance and API limitations.
Despite these limitations, WhatCable remains a powerful tool for Mac users, offering a unique perspective on the performance and capabilities of their USB-C cables. As Morley continues to update and improve the app, it will undoubtedly remain a valuable resource for tech enthusiasts and professionals alike.
