It looks great on paper. USB tester FNIRSI FNB-C2. New product.

News2026-03-14

In short:

The FNIRSI FNB-C2 is a new USB tester supporting USB Power Delivery 3.1 (PD3.1) up to 240 W. It includes a 20-bit ADC for high-resolution voltage and current measurement, supports reading and emulating e-Marker chips in USB-C cables, and recognises a wide range of fast-charge protocols – QC2.0/3.0/4/5, UFCS, Huawei FCP/SCP, OPPO VOOC/SVOOC and VIVO VFCP. Real-time monitoring of voltage, current, power and temperature. The price is below 1000 Kč (~$40), making it more attractive than the older FNB58 model.

I received an email about a new product from FNIRSI. A new USB tester called FNB-C2. And it looks really good.
It supports the PD3.1 standard, can measure up to 240W (20V/6.5A), can read e-Marker USB-C cables, and can also emulate them!

I have written about FNIRSI products often here. Initially, I was somewhat disappointed; however, the products from the last two reviews pleasantly surprised me.
We will see how the FNB-C2 performs; it promises a lot, and with a price under a thousand crowns, it is indeed an interesting product.

I tested one USB tester, the FNAC-28, and it didn’t turn out the best. On the other hand, it is the cheapest option among their testers, but USB-PD support is a must for me.

What will this one be like? It promises a lot.

Allegedly, it has a 20-bit resolution ADC converter for measuring voltage and current. The voltage measurement range is from 4 to 50V with a resolution of 0.000001V and an accuracy of ±0.2‰ + 2 digits, while the current measurement range is from 0 to 6.5A with a resolution of 0.000001A and an accuracy of ±0.5‰ + 2 digits, allowing it to reliably measure output power up to 240W.

Author’s consideration: If the tester has a resolution of 0.000001V, i.e., 1uV, and an accuracy of ±0.2‰, i.e., 0.02% + 2 digits (considering the measured value). Then the measurement inaccuracy (for 5V) could be ±1.002mV.

In addition to USB-PD 3.1 EPR, it also supports other fast charging standards – UFCS, QC2.0/3.0/4/5, Huawei FCP/SCP, OPPO VOOC/SVOOC, and VIVO VFCP.

The FNB-C2 can identify the e-Marker in a USB-C cable. You can easily verify whether the cable can actually handle the promised power. The USB tester can behave like a cable with or without an e-Marker chip.

There is also the option for real-time monitoring of both temperature and voltage, current, and thus power.

I have already ordered the tester. Delivery is within 14 days, and it is currently on its way via Zásilkovna.

You can find the product page at https://www.fnirsi.com/products/fnb-c2

The price is 851 CZK excluding VAT and shipping, making it cheaper than its predecessor FNB58 (1288 CZK).

Specifications

You are asking

Which fast-charging protocols does it support?

USB Power Delivery 3.1 (including EPR up to 240 W), Qualcomm Quick Charge 2.0/3.0/4/5, UFCS, Huawei FCP and SCP, OPPO VOOC and SVOOC, plus VIVO VFCP. It also handles e-Marker reading and emulation for USB-C cables – useful when checking whether a cable can really do the rated current.

What's the price?

Roughly under 1000 Kč (about $40), which is significantly cheaper than the older FNB58 with similar features. It's also more cost-effective than the FNAC-28, but – in contrast to the FNAC-28 – the C2 includes UFCS support.

Is the measurement accuracy good enough for serious work?

Yes – the 20-bit ADC offers high resolution and decent accuracy for voltage and current measurement. For deep diagnostics or power-electronics work it doesn't replace a Keysight or similar lab gear, but for a hobbyist or smartphone repair work it's plenty.

How does it differ from the FNIRSI FNAC-28?

FNB-C2 supports USB-PD 3.1 EPR (240 W) and UFCS – the FNAC-28 does neither. So if you need to test newer phones with UFCS or EPR notebook chargers, FNB-C2 is the better choice. The FNAC-28 is fine for older PD/QC standards.

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Measuring Equipment, Product Reviews, USB-C

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It looks great on paper. USB tester FNIRSI FNB-C2. New product.

You are asking

Which fast-charging protocols does it support?

What's the price?

Is the measurement accuracy good enough for serious work?

How does it differ from the FNIRSI FNAC-28?

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