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King Kévin f57ff3efbf doc: define aka 5 days ago
kicad lib: add QR code 2 months ago
library@08270e9b99 lib: update repo 6 days ago
picture doc: add LED picture 5 days ago
.gitignore restart with KiCAD 2 months ago
.gitmodules update library 5 months ago
.qeda.yaml lib: add used parts 2 months ago
CHANGELOG.md doc: document v1 changes 6 days ago
DEVELOPMENT.md restart with KiCAD 2 months ago
JLCPCB_CORRECTION.csv doc: fix some part position 6 days ago
LICENSE.txt add CERN-OHL-S license 1 year ago
Makefile make: make panel fab first 4 weeks ago
README.md doc: define aka 5 days ago
bom.ini rake: add BoM configuration 2 months ago
fp-lib-table brd: complete first layout 2 months ago
refdes2fab.py add script to move refdes to fab layer 2 months ago
sym-lib-table restart with KiCAD 2 months ago
usb-ac_cable_tester.kicad_pcb brd: fix text width 4 weeks ago
usb-ac_cable_tester.kicad_pro sch/brd: fix ground pad 4 weeks ago
usb-ac_cable_tester.kicad_sch sch: add position correction 4 weeks ago
version switch to v1 to improve design 2 months ago


The USB-A to USB-C (aka. USB-AC) cable tester shows which features a USB-A to USB-C cable supports.


Devices using the USB-C connector become more common, but most computer hosts still use USB Type-A (aka. USB-A) connectors. Thus USB-A to USB-C cable get widespread. But there is no indication on the cable about its intended usage: just power or charge the device, also allow data transfer, or even support fast data transfer. The USB-AC cable tester identifies the capabilities of USB-A to USB-C cables.


The USB-AC cable tester is powered by a CR1220 coin cell battery. Plug both ends of the USB-A to USB-C cable in the USB-AC cable tester and read the lights:

  • POWER: can be use to power a device (the VBUS and GND wires are present).
  • USB 2.0: can be use for USB 2.0 data transfer (the D+ and D- wires are present).
  • SHIELD: the cable is shielded, important for USB 3.0 Super Speed data transfer.
  • USB 3.x: can be used for USB 3.0 Super Speed (SS) data transfer (the 2 differential pairs are present).
  • Rp: the Rp pull-up resistor is present, required for USB-C orientation detection. Without Rp, the device might not turn on, or data transfer to normal or super speed might not be possible.

Fast charging: when connecting two USB-C devices, Rp is used by the source (e.g. host) to indicate to the sink (e.g. device) how much power it can draw (up to 0.5, 0.9, 1.5, or 3.0A). This capability is not supported by USB-A to USB-C cables, which restrict to the default USB power capabilities (0.5A for USB 2.0, 0.9A for USB 3.x). USB-C Power Delivery is also not possible using such cables. USB Battery Charging (BC) and other proprietary charging standards using the USB data lines might still be possible, but depend on the charger, and is outside the scope of this tester.