CableCheck Companion

⚠️ WebUSB not available

This page needs Chrome or Edge on a computer (WebUSB). If you opened the file directly and the Connect button stays dead, serve it locally instead:

cd companion && python3 -m http.server 8000 → open http://localhost:8000

Run a cable test

1

Install CableCheck on the phoneThe Android app answers this page over the cable. Open it once so it's ready.

2

Plug the phone into this computer with the cable under testUse the exact cable you want to judge. Unlock the phone.

3

Connect & switchPick your phone in Chrome's device chooser. The page switches it into accessory mode.

4

Approve on the phone, reselect, test runsTap OK when the phone asks to open CableCheck, then pick the phone once more here.

Only show phones in the device picker — hides headsets, hubs and audio devices ("Phone Calls" etc.). Untick if your phone's brand is missing from the list.

Idle — plug in the phone and click Connect.

💡 If the phone charges but never shows up in the device chooser, the cable is very likely charge-only (no data wires) — that is itself a result. On Windows, the accessory device may need the WinUSB driver (install via Zadig) before Chrome can claim it.

Testing…

0

Mbps

1

Handshake

2

Upload (computer → phone)

3

Download (phone → computer)

4

Latency (20 ping/pongs)

Your cables

Nothing saved yet — run a test above. Scores are relative to the best cable you've tested here.

⚠️ WebUSB not available

Run a cable test

Testing…

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USB standards ladder

Save this cable

Your cables