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Customer Review
Monba USB Micro-b receptacle to Type-C adapter does NOT follow the USB spec, will not charge Chromebook Pixel
Reviewed in the United States on November 3, 2015
Benson here. I am an engineer on the Chromebook Pixel and Pixel C teams at Google. I bought this cable to use various USB micro-b type cables with the Chromebook Pixel, and I found that this adapter does not work to charge the Chromebook Pixel.
Upon closer inspection, this cable does NOT comply with the USB Type-C specification version 1.1. The documentation can be found at usb.org under developers/usbtypec.
Specifically, these adapters do not charge the Chromebook Pixel 2015 because the adapters leave the C-C lines floating, where the specification requires a Rp pullup to Vbus to identify the cable as a legacy adapter or cable.
Please see Section 4.11 of the document named "USB Type-C Specification Release 1.1.pdf" and the following note :
1. For Rp when implemented in the USB Type-C plug on a USB Type-C to USB 3.1 Standard-A Cable
Assembly, a USB Type-C to USB 2.0 Standard-A Cable Assembly, a USB Type-C to USB 2.0 Micro-B
Receptacle Adapter Assembly or a USB Type-C captive cable connected to a USB host, a value of 56 kΩ
± 5% shall be used, in order to provide tolerance to IR drop on V BUS and GND in the cable assembly.
Since this is a USB Type-C plug to a USB 2.0 Micro-B receptacle assembly, the manufacturer must use a resistor of value 56kΩ as a pullup. This adapter does not do this.
If you're looking for a USB Type-C adapter that is compatible with Pixel and other future devices that follow the USB Type-C specification, do not use this adapter.
Upon closer inspection, this cable does NOT comply with the USB Type-C specification version 1.1. The documentation can be found at usb.org under developers/usbtypec.
Specifically, these adapters do not charge the Chromebook Pixel 2015 because the adapters leave the C-C lines floating, where the specification requires a Rp pullup to Vbus to identify the cable as a legacy adapter or cable.
Please see Section 4.11 of the document named "USB Type-C Specification Release 1.1.pdf" and the following note :
1. For Rp when implemented in the USB Type-C plug on a USB Type-C to USB 3.1 Standard-A Cable
Assembly, a USB Type-C to USB 2.0 Standard-A Cable Assembly, a USB Type-C to USB 2.0 Micro-B
Receptacle Adapter Assembly or a USB Type-C captive cable connected to a USB host, a value of 56 kΩ
± 5% shall be used, in order to provide tolerance to IR drop on V BUS and GND in the cable assembly.
Since this is a USB Type-C plug to a USB 2.0 Micro-B receptacle assembly, the manufacturer must use a resistor of value 56kΩ as a pullup. This adapter does not do this.
If you're looking for a USB Type-C adapter that is compatible with Pixel and other future devices that follow the USB Type-C specification, do not use this adapter.
