What's actually plugged into each port.

Plug it in. See what it really is.

USB-C ports look identical. They behave wildly differently. Cable Detective shows the truth for each one.

• Power direction and wattageWho's charging whom, and at what negotiated wattage. PD contract source, advertised PDOs, charger rating.
• DisplayPort lane stateHow many lanes are running, at what link rate. Whether DP-Alt Mode is actually active.
• Cable identitySOP / SOP' / SOP" e-marker reads. Vendor IDs decoded. No invented specs when the cable doesn't answer.
• USB transportUSB 2.0 vs 3.x SuperSpeed vs USB4 vs Thunderbolt. The lane state, not the marketing on the box.
• Plain-English explanationOptional Apple Intelligence layer that summarises the report. Off by default. On-device only.

10 cable problems this app actually solves.

Every one of these is a real pain point people post about. Cable Detective tells you which side - the cable, the charger, the device, or the port - is the cause. No guessing.

1. "My MacBook is charging way slower than it should." The label says 96 W, the Mac says 30 W. Cable Detective shows the negotiated USB-PD contract, every PDO the charger advertised, and whether the cable's e-marker rating is the bottleneck (un-e-markered cables cap at 60 W).
2. "I plugged in an external display and got nothing." Some USB-C cables carry data only and no DisplayPort lanes. Cable Detective shows whether DP-Alt Mode is active, how many lanes are running, at what link rate (RBR/HBR/HBR2/HBR3/UHBR), and how many display sinks the controller sees.
3. "My USB-C SSD is writing at 40 MB/s instead of 1 GB/s." The cable says SuperSpeed on the box but the link is running USB 2. Cable Detective shows active vs supported transports for that exact port, so you know whether the cable, the enclosure, or the host downgraded the link.
4. "Is this cable counterfeit?" Real USB-C accessories carry a PD e-marker chip with a USB-IF vendor ID. Cable Detective decodes the SOP / SOP' / SOP" identity, shows the vendor against the official USB-IF database, and tells you if the cable simply has no e-marker (very common, not necessarily fake, but caps power at 60 W).
5. "My Thunderbolt dock isn't running at full speed." Thunderbolt 4 vs USB4 vs USB-C 3.x are easy to confuse. Cable Detective shows the actual Thunderbolt link speed for that port and whether the dock negotiated TB or fell back to USB-C.
6. "Cable Detective said 'liquid detected' before macOS even popped a warning." The USB-C controller exposes a Liquid Detection (LDCM) signal long before the system-level dialog appears. We surface it directly so you can stop charging before damage spreads.
7. "This cable works in port 1 but not port 4." Different USB-C ports on the same Mac can have different controller chips and capabilities. Cable Detective shows you the per-port active and supported transport list, the controller chip, the firmware revision, and the plug event count - so you can see when a port has been physically damaged.
8. "My Anker hub disappeared from the system." When a hub is connected the Mac sees one USB topology root and many devices behind it. Cable Detective lists every device attached behind the hub, in physical port order, with vendor IDs and class info - so you know whether the hub itself is gone or just one downstream device.
9. "I'm travelling and want to know if this random charger is really 100 W." Cable Detective shows the charger's full PDO menu (every voltage / amperage offer it advertises), the rated maximum, and the watts you are actually pulling right now. If a no-name charger only advertises 5 V / 3 A, you'll know before you trust it overnight.
10. "I have a drawer full of identical-looking USB-C cables. Which one is which?" Plug each cable in for a few seconds. Cable Detective reads the e-marker chip (when present) and shows the vendor (decoded against the USB-IF database), product ID, declared speed class, current capability and EPR support. For cables with no e-marker chip - very common - it shows what the cable actually negotiates with your Mac, so you can tell a real SuperSpeed or Thunderbolt cable apart from a charge-only USB 2 cable by behaviour, not by squinting at moulded plug colours.

Requirements

Mac

Apple Silicon (M-series). Intel Macs not supported.

macOS

26 (Tahoe) or later.

AI feature

Optional. Requires Apple Intelligence enabled in System Settings.

Permissions

USB device entitlement. No file access, no network, no camera, no microphone.

Pricing

Common questions

Why does my "USB-C" port only do USB 2.0?

Because the cable, the host port, or the device chose to. Cable Detective tells you which one. SuperSpeed needs a SuperSpeed-capable cable on a SuperSpeed-capable port — many bundled cables are USB 2.0 only.

It says my charger is delivering 86 W. The label says 96 W. Bug?

No. 86 W is the negotiated USB-PD contract right now (laptop's request × charger's offer × cable rating). The charger's capability is on the box; the negotiated contract is what's actually flowing.

Can it tell me if my cable is fake?

It can tell you what the cable's e-marker chip claims (or that it has none). It cannot test the conductor quality. A cable that lies in its e-marker is rare; a cable with no e-marker chip at all is common and limits negotiated wattage to 60 W.

Does it work on Intel Macs?

No. Apple Silicon only.

Does the AI explanation send anything to a server?

No. It uses Apple's on-device Foundation Models. The app has no network entitlement at all.

Is there a free trial?

No. Cable Detective is a one-time €9.99 purchase on the Mac App Store. No subscription, no account, no recurring charge, no upsell. You buy it once and that version is yours for life. The Mac App Store does not support trials for paid apps, so we do not offer one - the FAQ, the screenshots on this page, and the live demos in App Store reviews are how you decide before you click buy.