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⚡ Power up your USB IQ — test smarter, charge faster!
The FNIRSI FNB58 is a compact, professional USB tester featuring multi-port compatibility (USB-A, Micro-USB, Type-C) and a crisp 2.0-inch TFT display. It supports comprehensive fast charge protocol detection including PD2.0/3.0, QC2.0/3.0, VOOC, and Super VOOC, enabling precise voltage, current, and power monitoring. With advanced features like E-Marker cable chip reading, cable resistance measurement, and real-time ripple analysis, it empowers tech-savvy professionals and enthusiasts to validate chargers, cables, and power delivery setups with confidence. Its data logging and app integration make it an essential tool for anyone serious about USB power performance and fast charging optimization.
















| ASIN | B0BJ253W31 |
| Best Sellers Rank | #16,980 in Tools & Home Improvement ( See Top 100 in Tools & Home Improvement ) #17 in Voltage Testers |
| Brand | FNIRSI |
| Brand Name | FNIRSI |
| Color | multi-color |
| Compatible Devices | USB interfaces, mobile phone chargers, U disks, mobile phones, mobile power supplies, USB-A, Micro-USB, Type-C devices from various brands |
| Customer Reviews | 4.3 out of 5 stars 519 Reviews |
| Included Components | USB Tester |
| Item Weight | 1.6 ounces |
| Manufacturer | FNIRSI |
| Measurement Type | Voltage, Current, Fast Charge Detection, Etc |
| Min. Operating Voltage | 4 |
| Minimum Operating Voltage | 4 |
| Model | FNIRSI-001 |
| Part Number | FNIRSI-001 |
| Power Source | Battery Powered |
| Specification Met | Ul, Iec |
| Style | FNB58 |
| Style Name | FNB58 |
| Unit Count | 1 Count |
| Upper Temperature Rating | 40 °C |
R**H
Great USB Test Tool, Terrible Manual
After spending a week learning about and experimenting with this FNIRSI FNB58, I've found it to be a very valuable tool for testing, sorting, and upgrading USB hubs, power supplies, and cables! It is especially useful for learning about and testing the newer USB 3.2 capabilities, power options, and especially what Type-C cables will and won't work for the new Power Delivery (PD) and Fast Charge features! But the official FNB58 manual available is worthless, due to lack of detail, poor organization, and lousy translations. It's hard to figure out what practical purposes this great tool has for home use. So here are some of the most useful features I've found from my testing. • Basic Monitoring: Using the USB-A or USB-C input/output ports, the screen will display voltage (V), current (A), power (W), and protocol in real-time, as dynamic numeric data or “oscilloscope” graphs. • Read USB-C Cable E-Marker Chips: Higher-end USB-C cables have an embedded IC chip that reports capabilities of the cable to the PD power source. This allows the power source to provide higher voltage and wattage through the cable for higher-powered devices, up to the limits of the cable. If there is no chip in the cable, your expensive new USB power adapter will only be able to supply up to 60W of power instead of the 240W you paid for! Do you know which of your cables will work for your higher power laptop? The “Toolbox” option “USB-C Cable” quickly and easily reads this chip, if present, so you'll know what that cable supports. • Fast Charge Triggering (Protocol Test): Navigate to the “Fast Charge” menu to test for USB charger capabilities, like PD, Apple, Battery Charging (BC), Samsung, Huawei, or QC (Qualcomm) fast-charge protocols. Once capabilities are detected, higher-voltage power protocols can be triggered, changing the output voltage and current settings on the USB power wires. Warning: Do NOT connect sensitive, non-fast-charge devices when triggering higher voltages (9V – 20V) as it can damage them. Some of the protocols (like the PD or QC 3.0) have variable voltage adjustments, so you can set the output voltage to anything between the protocol limits (like 3.3V-20V) in 0.02V increments. You can thus even use the FNB58 and an appropriate charger as a variable power supply for small low-power projects! • Cable Resistance Testing: On the "Toolbox" menu option, the "Cable Resistance Detection" feature can measure the resistance of a connected USB cable. For most accurate results, a separate constant-current electronic load device, like the Drok USB Load Tester, is required on the output of the FNB58. • Offline Recording/Data Logging: The FNB58 has options for recording power consumption over time. This allows testing of possible intermittent problems. The photos here show the results of some of the testing I've done with the FNB58. The "USB-C Cable" screen photo shows the results of testing a USB Type-C cable that DOES have an E-Marker Chip embedded in the cable's connector. Plug the Type-C cable to be tested into either the Type-C “IN” or “OUT” port. Only one end of the cable needs to be plugged in for this test. Use the rocker switch on top to navigate to the Application page. Select the Toolbox option, then select “USB-C Cable” (or “USB-C E-Marker” on earlier firmware). This will display the values embedded in the cable’s E-Marker chip, which provides the USB power source with the capabilities of the cable like cable speed (example: “USB 3.2 Gen2”), cable length specification, max cable voltage and current, hardware and firmware levels, and cable vendor ID. If the cable can handle it, the power source may select higher voltage and power for higher-powered devices. Without this chip and the resulting negotiation with the power source, output is limited to 60W (some USB power sources have the option of providing up to 240W). The image with three screen-shots shows the different capabilities between ports on the same charger. Chargers often support different USB power protocols and protocol values, depending on the port being used. For example, this photo shows three USB-C ports (C1 – C3, top to bottom) on the same charger, each with a different set of protocols and supported voltage/power values. Note the discrepancy between the label on the charger (last photo) and the values being read by the tester. When triggering the protocols (see below), what I was able to get out of the charger were the voltages listed on the tester, not always what was printed on the back of the charger. Some of the values are limited because of the standard for the protocol, like the BC 1.2 (DCP), which limits the output to 5V at 1.5A. But the labeling on the charger can mislead you about what output you’ll actually be able get from it! The FNB58 "Fast Charge" option's "Automatic Detection" feature displays the power source's supported protocols, and their voltage limits for each USB port. This also helps clear up some discrepancies between the charger's specs and the actual port output. The image with the multi-meter at the top shows the results of one of my power source output tests. Once the available fast-charge protocols have been detected (like above), you can "trigger" any of the protocols with the FNB58, to set a specific output voltage. I did physically test the output of the charger after triggering the protocol, to verify the charger actually did change output voltage. My multi-meter tests correlated closely to the output voltages shown on the tester after triggering the protocol settings. The voltage manually selected in the tester is shown outlined on the left of the tester’s screen (10.00V here). The actual voltage as measured by the tester is shown with the green background on the screen in the upper right (10.239V here). The external voltage measured by the multi-meter here is fairly close, at 10.28V. Each protocol has different voltage selection options. To test these, navigate to the Application page of the FNB58, select the Fast Charge option, then the PD Trigger option. BE CAREFUL, this can damage some devices connected to the output of the tester - read the on-screen warning, and read the manual! See the end of this review for some links to helpful supplemental information. The final "Qualcomm QC2.0" screen photo shows voltage selection options for this protocol. Most protocols have only certain fixed voltages available too, so the Fast Charge option for each of the other protocols shows only those voltages available for activation. I hope you find some of this information useful!
O**L
Lets you see what going on!
Ok, every have one of those days when the cables you're using for charging is not working? Well wonder no more. I found this device to be a life saver when it comes to removing fustration. Not only does this device lets you what cable is charging best. It allows you to see at what voltage, current and several other items. When charging your devices you can see if the charger for cable combination is restricting the strength of your charging for your device. It's compact design allows it be travel friendly. Since it uses the source of the charge no battery is required for it's use. The instructions for this device is straight forward as well as it being very accurate when one is trying to resolve charging connections between devices. One idea is using it to eliminate cables that won't allow those charging blocks that fast charge to be identified. Overall, this is one device with multiple uses. As for cable types if supports both USB-C as well as USB-A.
A**.
✅ Accurate, compact, efficient and sufficient
I am providing an overall comment for three USB testers, all of which deserve to be purchased as they complement each other perfectly and are consistent in their results. I would like to dedicate the majority of this review to the Bit Trade One model, which has recently arrived on Amazon. It deserves a shoutout because the tool is exceptional and inexpensive for what it offers. The ADUSBCIM is a USB cable tester that truly complements traditional USB cable testers. Only the cable to be tested needs to be plugged into the A and B ports, and the tool does the rest. The reference value for calculating the cable's resistance is taken using a CR2032 battery, and I note that the calculation is very precise and stable. You can find on Bit Trade One's ADUSBCIM GitHub page, in the Pull Request section, a manual in English in PDF format. This is my small contribution to the project, as the current official English manual is more of a word-by-word description that is difficult to understand. Thanks to this tester, I discovered, for example, that Anker cables, the 765 series, were actually poor high-resistance cables, and that I had much better options for charging. I ended up wasting money on cables that turned out to be slower than cables that were given to me for free with computer accessories. The FNIRSI FNB58 is a very comprehensive USB-A and USB-C port tester. It notably offers numerous rapid charging protocol tests, can test the quality and resistance of a cable, and obtain oscilloscope-like graphical representations. Now that we are on PD3.0 and with PD3.1 approaching quickly, owning one of these tools is now essential to validate the proper functioning of an installation. I've read a lot of advice on Reddit, and if you're looking to equip yourself with the best products offering the most testing possibilities, here are the tester references to get: - Bit Trade One ADUSBCIM (very thorough cable tester testing all the lines of a cable) - FNIRSI FNB58 (the most comprehensive, many ports, many scenarios, USBA/C Micro) - ChargerLab KM003C (the most modern, TB4, 250W) If you have these three or at least a combination of the cable and usb tester, it will take you no more than a few days to become a USB expert. 👌
E**C
Awesome tool but be *VERY CAREFUL* about triggering voltages or checking chargers for capabilities.
Per the title. Awesome tool but you need to be EXTREMELY careful about triggering voltages or checking chargers for capabilities. This tool will trigger high voltages and check the charger for what features, USB-PD profiles, Qualcomm QC features, and other charging standards it supports. When using the feature checking *MAKE ABSOUTELY SURE* you have NO DEVICES at all hooked up to the tool besides the charger in question. This includes NOT having the USB-A ports plugged into something else when testing USB-C charger etc. Bascially just make sure you ONLY have the charger you are testing plugged in. For advanced usage this has a manual PD trigger with PPS support to allow you trigger a specific PD profile or fine PPS voltage with current limits. Very useful as like a low current lab power supply. Again, this is an advanced feature with no guardrails and you will blow up devices if your not careful and use the wrong voltage or attempt to use this with a PD device not expecting that voltage. Note there is two versions this blue one is the one with bluetooth support while the black one there is none. I think it would honestly be better if the black one was discontinued to avoid confusion given the price differences are extremely minimal. Also, A cap for the USB-A port would be a nice touch so you don't have to buy one yourself. I should have bought one of these years ago!
A**R
Good usb tester with PD trigger capability
I’ve been impressed with the FNIRSI USB tester’s build quality. Unlike many testers on the market, which often resemble beta models with open sides or no casing, the FNIRSI is encased in a professional housing with input ports for USB-C, Micro USB, and USB-A. I’ve used the USB-C eMarker check to test cables, which works well. The tester is supposedly capable of measuring cable resistance, but I haven’t figured out how to do this yet. Instead, I purchased a Treedix cable tester, which is battery-powered and can measure resistance. Treedix also includes a Lightning port for testing Apple cables. I’ve tested several battery banks to verify if they deliver the power promised in their advertising. The included instructions were minimal, but I found documentation on the FNIRSI website. Initially, I struggled to trigger higher Power Delivery (PD) voltages (beyond the standard 5V) on the USB load meter. Watching YouTube videos helped me navigate the PD trigger menu effectively. A firmware update is available on the FNIRSI website, but I haven’t applied it yet, as the accompanying app seems unreliable. I plan to test it on a sandboxed PC to ensure safety. I liked the tester so much that I bought a second unit. This allows me to use the PD trigger to test the load on multiple ports of a power bank simultaneously. I’m still learning how to fully utilize the tester, particularly the PC logging feature, which I hope to explore further.
D**D
Terrible user manual translation
This power tester is awesome. I have a bunch of USB-C to C cables and I lost track of which ones were 60w, 100w, or 240w. This tool helped a lot. I have since labeled the cables accordingly. It even helped me realize that a few of my cables were capable of USB 3.2 data transfers when I thought they were just USB 2.0. I tested it and confirmed it. The user manual is horribly translated. One very helpful reviewer here provided much clearer instructions which helped me figure out how to use this tester properly. I am done using it for the moment but any new cables I purchase will go through this tester. Well worth the price.
E**P
Awesome meter with great features!
Good quality USB meter which allows USB data passthrough, the readings look accurate when compared to the measurements from my 737 power bank. It is simple to navigate, and can also test battery capacity which is very useful and it also allows you to set the battery voltage and estimated charging efficiency with 10 profile save slots available. I recommend keeping the device plugged in with the top left micro USB port to stop the unexpected power offs while testing, and for when you want to keep the toggle switch "pd com" as off which will bypass the fnb58 handshake with the charger and instead allows USB C negotiation directly between the phone and charging brick.
S**O
A decent, affordable USB tester that has it share of issues
Sadly in order to obtain a decent USB tester in the past that performs more than common functions you had to deal with stacked exposed circuit boards held together with screws at the corner. No case, plenty of risk of debris getting directly on the circuit boards and causing havoc with the device. If anything metallic gets between the boards during operation, the result is usually catastrophic (I've been there). The FNB58 OTOH is a much much more of a finished product. It supports USB-A, microUSB, and USB-C that includes power delivery testing testing capabilities that go far beyond just a Volt/Amp/Watts meter. However, it does have some issues, and one that I found that is particularly concerning to me is its protocol snooping feature known as PD Listener. The PD Listener is supposed to allow you to see not only the charging protocol in use but also the fixed and augmented power delivery options (FPDOs and APDOs) that are in effect at any point in time. This is especially important if you are trying to debug a charging issue. The problem is that PD Listener seems to have issues with Samsung phones that use PD-PPS. I have been working with Finrsi on this issue for the past few weeks. After my troubleshooting and providing data to Finrsi, they have confirmed my concern that the FNB58 has compatibility issues with Samsung phones using PD-PPS. Pending them acquiring Samsung phones to further investigate and resolve this, it will remain an open product issue. They were not able to provide me with a expected time for a fix. In light of that, if you have a Samsung phone using PD-PPS (like the S24+ phones I was testing) and need a USB tester to identify not only which charging protocol is in use but also which FPDOs and APDOs have been negotiated in real time, I'd suggest you look instead at the ChargerLab KM003C instead. The KM003C and its detailed protocol analyzer is what I used to troubleshoot the issues I had with the FNB58, and it worked perfectly. Absolutely worth every penny IMHO. Hopefully, Finrsi will fix this in the FNB58 firmware. But until then, if you want the FNB58 mainly for its features OTHER THAN PD Listener, then it is still a viable product. But if you are looking for a tester and PD protocol analyzer specifically for USB-C, it I'd strongly recommend the KM003C to you hands down.
A**R
Best for price, better than impoprting.
Best for price, works as intented. Make sure to use input for input only, and same for output. Flickers a bit when undervolted. Firmware update make sit work more good. Bluetooth app by FNIRSI works only after GPS is turned on and pairs only via app. Its weird n unnecessary yet ok. Accuracy is fine maybe 1-2% vary.
G**E
For accurate results buy this
Very glad that I did not buy a cheaper option. This is a great peice of Tech to own.
J**A
Muy completo
Excelente producto superó mis espectativas
C**U
Buen medidor
Vi varias reseñas en YT y todas apuntaban a este medidor de entre muchos. Hace la función y adicionales pero la calidad de fabricación externa se siente algo barata.
A**.
doesnt display mah
Doesnt display mah which is what i needed this for. Displays absolutely everything else but. Annoying it doesnt show basic mainly used use case of battery capacity, but makes you work it out from other measures. Has many screens, not on any of them, cannot set it to display mah, very hard to use overall vs many other similar products - so expensive and got a lot of stuff i dont need with it, and not the basic function i do need.
Trustpilot
1 week ago
1 month ago