D.I.Y.

USB testers

I am using 3 USB testers to perform USB cable testing

• Power-Z KM003C (Amazon), (AliExpress) 

  • The device is used ​for reading eMaker chip parameters, usb protocols, and Thunderbolt version.

  • Device firmware version: v.1.9.5

• FNIRSI-FNB58 USB Tester (Amazon), (AliExpress)

  • ​The device is used to perform cable resistance tests.

  • Device firmware version: v0.68

• Treedix USB cable tester (Amazon)

  • I use this tester to determine which pins of the cable are used to determine if the cable is for charging only or supports usb2.0/3.0 or a higher speed interface.

• BitTradeOne USB Cable Checker2 (Amazon.com)

  • I purchased this Japanese usb tester for visual convenience and to speed up the cable testing process since it has a screen. The tester is able to determine the resistance of the cable, which allows you to do without UsbA-UsbC adapter (used for FNB58). Also this tester shows the presence and value of the resistor installed in UsbA-UsbC cables on the CC pin. The resistance value is determined consistently 60mOhm higher than the FNB58, which is more accurate, so I take into account the 60mOhm correction when testing.

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Cable eMaker chip, USB protocol, and other parameters

• eMaker chip - this is a special chip inside the usb-c plug which takes part in communication between a charger and a charged device (or between two connected devices). eMaker chip does not require to be installed for the 60W cables (maximum current is up to 3A). The eMaker chip sends information to charger and connected devices about cable characteristics like:

  • Supported charging protocol (including max.current and voltage). This is how a charger could distinguish cable maximum power: 60W(up to 20V3A) vs 100W (up to 20V5A) vs 240W(up to 48V5A) and determines proprietary cables.​

  • Thunderbolt technology support and its version. Since Thunderbolt version 3 this technology exploits UsbC cable type. There are a few articles I can advise: Thunderbolt 4 vs USB4 and Thunderbolt 4 vs. Thunderbolt 3 vs. USB4 vs. USB 3 and announcement of Thunderbolt 5, First Batch of Thunderbolt 5 Devices Launched.

  • Display port alternating mode (over UsbC), supported starting from USB3.1 cables, but for a USB port on a device the special Display Port marking must be present or the port must be TB3/4/5 or USB4 compatible. Here is the article about that technology.

  • USB protocol (USB 2.0/3.0/4 etc.). The transmission speed, for example, depends on it.

  • Passive or Active cable. The Active cables have a special circuit to boost the signal in order to support high-speed transmission in long cables because the signal quality is degrading due to interferences from surroundings.

  • Chip vendor.

  • If you want more information about eMaker chip you can read this article.

• USB protocols. There are many USB protocols on the market, starting from USB2.0 (480mbps data transmission speed) up to USB4 2.0 (80Gbps data transmission speed). You can read this article to get more information about protocols and markings.

• I can advise one more good article about data bandwidth needed for different screen resolutions and frequencies through DP (Display Port) which signal can also be sent over UsbC cable.

• Here is official cable and connector specification for UsbC cables.

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Type of cables

Not all cables can be used in quick/fast charging because cable producers might use inside cable only power and ground lines (VCC and GND) and ignore data lines. These cables can to be used in basic charging protocols like CDP, SDP, DCP (up to 1.5A) because higher voltages and more sophisticated charging protocols require data lines to negotiate them. That is why sometimes identically looking cables can or can't do fast charge.

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In this test I am focusing on cables that are using in quick/fast charging:

• UsbA-micro USB - can support QC (Quick Charge).

• UsbA-UsbC - these cables are more advanced and can be used in many charging protocols including proprietary ones from OPPO/OnePlus/Realme, vivo, Xiaomi/Redmi. These cables might have eMaker chip.

• UsbC-UsbC is the most advanced type of USB cable. The cable plug is universal, symmetrical, has multiple data lines and double power lines, can be used for standard charging protocols such as QC or PD (power delivery), as well as for proprietary protocols from Xiaomi and other manufacturers, as well as for advanced data transfer (USB4, Thunderbolt 3/4/5, DisplayPort video transmission). In such cables, there may be an eMaker chip that tells connected devices whether the cable meets a certain standard and power (100W/240W), data transfer speed, Thunderbolt version and other specific parameters. Keep in mind that sometimes cheap UsbC cables are not symmetrical as per the standard, so you may notice a difference in charging or data transfer depending on how you plug the cable in, but this is a violation of the USB standard and if you have such a cable, it's best not to use it.

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Cable resistance measurements