FNIRSI FNB48P vs FNB58

Choose the FNIRSI FNB58 first if you want a larger display for charger and cable diagnostics; choose FNB48P if its smaller screen suits you and you mainly need their shared testing functions. For either model, select BT for the Android Bluetooth route or Std. for use without that phone connection; FNIRSI lists Windows PC software and excludes iOS/macOS in its USB Tester Software section. These recommendations are based on official documentation, with the range and package caveats below.

Quick picks: decide the package before checkout

Compare specifications and all conditions

A larger display for regular charger checks

Our choice

FNB58

Check before ordering

Choose BT or Std. deliberately; the model name alone is insufficient

PD monitoring and cable-chip reading on the smaller display

Our choice

FNB48P

Check before ordering

Its own page lists these functions; obtain its exact electrical limits before planning demanding tests

Phone viewing through FNIRSI's app

Our choice

BT option of either model

Check before ordering

The documented app is Android

Wired computer recording

Our choice

Either model, with Windows

Check before ordering

Plan a Micro-USB data connection to the PC port

Official iPhone or Mac companion software

Our choice

Neither

Check before ordering

FNIRSI explicitly excludes these platforms for USB Tester Software

Full comparison table ↔

Swipe to compare. Row labels stay visible.

What you need	Our choice	Check before ordering
A larger display for regular charger checks	FNB58	Choose BT or Std. deliberately; the model name alone is insufficient
PD monitoring and cable-chip reading on the smaller display	FNB48P	Its own page lists these functions; obtain its exact electrical limits before planning demanding tests
Phone viewing through FNIRSI's app	BT option of either model	The documented app is Android
Wired computer recording	Either model, with Windows	Plan a Micro-USB data connection to the PC port
Official iPhone or Mac companion software	Neither	FNIRSI explicitly excludes these platforms for USB Tester Software

What you need	Our choice	Check before ordering
A larger display for regular charger checks	FNB58	Choose BT or Std. deliberately; the model name alone is insufficient
PD monitoring and cable-chip reading on the smaller display	FNB48P	Its own page lists these functions; obtain its exact electrical limits before planning demanding tests
Phone viewing through FNIRSI's app	BT option of either model	The documented app is Android
Wired computer recording	Either model, with Windows	Plan a Micro-USB data connection to the PC port
Official iPhone or Mac companion software	Neither	FNIRSI explicitly excludes these platforms for USB Tester Software

The current FNB48P page and FNB58 page offer both BT and Std. selections. Select the exact option on the destination page; a photograph or family title should not decide your package.

FNB48P vs FNB58: the useful comparison

These are manufacturer specifications and documented functions, not our readings.

Sources: FNB48P specifications and functions, FNB58 specifications, FNB58 manual, and software compatibility.

Resolve the limits before buying for high power. FNB58's product page and its linked manual disagree on maximum power: 140 W versus 120 W. Get confirmation for the exact hardware/firmware revision if your intended use depends on that difference. Its documented 28 V monitoring ceiling also limits the decision independently of the watt figure; a protocol name does not override that ceiling.

Keep the FNB48P evidence separate. FNIRSI's Chinese product page calls its model FNB48, while its English store sells FNB48P. We have not transferred that differently named page's electrical ranges to this comparison. Read the FNB48P manual and confirm the limits for the package you order.

First choice for the larger screen: FNIRSI FNB58

The reason to choose FNB58 is straightforward: its 2.0-inch display gives you a larger screen than FNB48P's 1.77-inch display. Both advertise PD monitoring, cable-chip reading and waveform functions, so we would not upgrade solely to obtain those shared features. FNIRSI's FNB58 page documents the functions and connectors.

The manual's connector diagram identifies a USB-A male input, USB-C female input, Micro-USB monitoring input, USB-A female output and USB-C female output. A separate Micro-USB PC port handles the computer connection. Do not confuse the monitoring Micro-USB socket with the PC socket when assembling a recording setup.

Choose FNB58 BT if Android viewing is part of the plan; otherwise select FNB58 Std. The published package list names only one FNB58 tester, and the page says there is no paper manual. Treat a data cable, load and case as unconfirmed inclusions until the exact offer specifies them.

See FNB58 packages at FNIRSI

Alternative for the shared functions: FNIRSI FNB48P

FNB48P's official page lists PD packet listening, QC-to-PD conversion, E-Marker/DASH chip reading, differential-pressure cable resistance testing and waveform recording. It also lists automatic screen rotation. That is a substantial function set if the smaller display works for your desk.

Its battery-capacity utility uses customizable battery voltage and conversion efficiency. Treat the result as a calculation using those settings; it does not independently establish the capacity of an unknown battery. FNB58's manual describes the same dependency for its capacity calculation.

Choose FNB48P Std. for use without the Android Bluetooth connection, or select FNB48P BT deliberately. The current English page does not enumerate a box-content list, so confirm the data cable and any accessories separately. We would choose FNB58 instead if clear published voltage/current limits are essential before ordering.

See FNB48P packages at FNIRSI

Windows, Android and firmware: match the software to the job

FNIRSI's software hub explicitly includes FNB48P and FNB58 in the USB Tester Software family. Its UsbMeter PC manual describes recording voltage, current, power, D+/D−, capacity and energy, saving records to the PC, and importing offline curves. That is a reason to plan the computer connection even if you do not need Bluetooth.

The linked Android app manual is titled for FNB48, despite being linked from the current shared software section. It instructs users to search and connect inside the app, rather than Android's system Bluetooth settings. Use it as shared app guidance; do not mistake that older title for a different meter's firmware instructions.

• Yes: Windows PC | FNIRSI lists UsbMeter for both models; plan the PC-port data cable.
• Partly: Android phone | Select BT hardware and connect inside FNIRSI's app.
• No: iPhone or Mac software | The USB Tester Software section explicitly excludes iOS/macOS.

On-meter features do not all become remote controls. The published PC manual lists remote triggering for QC2.0, QC3.0, Huawei FCP/SCP and Samsung AFC. The linked Android manual lists QC2.0/3.0, FCP and AFC. Neither list promises the meter's full trigger menu from the computer or phone; if remote PD control is your buying requirement, obtain current confirmation first.

At the official firmware hub, select the model under signal analysis, then USB testers. The retrieved catalogue lists FNB58 Firmware V1.15.zip and FNB48P/S Firmware V1.1.0.ufn in their respective entries. The latter links a file named Fnb48sV1.10.ufn: the shared P/S naming is documented, so select through the FNB48P entry instead of guessing from the filename. FNB48S is separately marked discontinued in the catalogue; sharing a download does not make the product names interchangeable.

FNIRSI's firmware page requires Windows 10 or Windows 11, says to extract the package first, and warns that updating through macOS can brick the device. Those are firmware-update requirements; they do not establish support for other operating systems in UsbMeter.

Buying guide: assemble a complete connection

For wired recording, the shared PC manual specifies Micro-USB at the meter. FNB58's upgrade instructions explicitly require a cable with data transmission. Choose that data cable to match your computer's available port, and do not assume a charging-only cable will serve the software connection.

For FNB58 PD listening, the manual calls for two USB-C-to-USB-C cables, with the meter between the charger and device, plus external power through the PC port. It specifies a supply no greater than 16 V, usually 5 V, for that external-power connection. The PC-port limit is different from the monitoring input's 28 V limit.

1. 1

   Pick the viewing device

   Choose Windows for the documented PC route, or BT hardware for Android.

2. 2

   Match the connection

   Plan a Micro-USB data cable for the PC port; FNB58 PD listening also calls for two C-to-C cables and external power.

3. 3

   Match the measurement

   For FNB58 cable resistance, add the constant-current load required by its manual; confirm what the offer includes.

Cable reading and resistance testing answer different questions. E-Marker reading retrieves chip information. FNB58's resistance procedure needs a constant-current load, with a reference reading and a reading after inserting the cable, at similar current. A phone's ordinary charging session is not the constant-current-load setup described in the manual. Follow the model-specific procedure rather than treating the toolbox label as a complete kit.

For a gift, establish the recipient's computer or phone platform before choosing BT or Std., and include the connection accessories their intended job requires. For the broader shortlist, use our USB-C power meter guide; for the cross-brand decision, read POWER-Z KM003C vs FNIRSI FNB58.

How we choose

We compared FNIRSI's product descriptions, model-specific manuals, shared software documentation and model-labelled download catalogue. These are documentation-based recommendations; we have not physically tested either tester. Screen preference is our buying judgment, and we do not claim a comparative accuracy or reliability advantage. The power-range conflict and model-name ambiguity remain explicit; see how we choose.

Verdict

Buy FNB58 for the larger screen; consider FNB48P for its shared core functions if the smaller screen suits you. Select BT only when the documented Android route is useful, and plan Windows plus a Micro-USB data cable for PC work. Before ordering, resolve the FNB48P limits or FNB58 power-range conflict wherever your intended measurements depend on them.