JOY it UM25C Measuring Device User Guide

To change the default language, disconnect the device from
power, press and hold any multifunction button, reconnect the
device, and keep the key pressed until desired language is
selected.

Main Menu (Measurement Results):

Voltage
Current

Accumulated electrical loading
Accumulated energy

Temperature Data group
Equivalent resistance

Power consumption

QuickCharge Detection:

The meter automatically recognizes devices with QuickCharge
support. Supported modes include QC2.0, QC3.0, Apple and Android
charging modes.

Recording of Charging Process:

To record the charging process, set trigger current for
recording and monitor accumulated electrical loading, energy, and
time.

Cable Impedance:

Measure cable impedance by connecting the device directly to the
power supply system or via data connection. Resistance of the data
connection cable can be measured.

Frequently Asked Questions (FAQ):

Q: How do I change the language settings?

A: To change the language, disconnect the device from power,
press and hold any multifunction button, reconnect the device, and
select the desired language on the display.

Q: What is the voltage measuring range of the device?

A: The voltage measuring range is between 4 to 24 volts.

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JT-UM25C
USB-Messgerät
1. GENERAL INFORMATION
Dear customer, Thank you for purchasing our product. In the following are information which you should note before commissioning. Whenever you have unforeseeable problems do not hesitate to contact us. Today, USB connections are not only found at PCs, but also at power banks, in cars or in trains. But not all connections are of best quality and deliver even currents and voltages. With the JT-UM25C, you always have all values in view. The meter supports additional functions such as Quickcharge 2.0 and 3.0, as well as Apple 2.4 A, 2.1 A, 1 A, 0.5 A and Android DCP, and also offers convenient evaluation via a wireless interface. With a measuring range of up to 24 V and 5 A, the JT-UM25C is suitable for practically all applications. The integrated 1.44″ LCD display can be regulated in five brightness levels and provides always an overview of all measured values.

2. DEVICE OVERVIEW
Voltage measuring range Current measuring range
Update rate Measurement accuracy
Temperature range
Display size Supported QuickCharge
modes

4 – 24 V 0 – 5 A
2 Hz 0,001 V / 0,0001 A
-10 – 100 °C
1,44″ QC2.0, QC3.0, Apple 2.4 A / 2.1 A / 1 A / 0.5 A, Android DCP, Samsung

BT switch
USB-A Port (female)

microUSB-Port 4x multifunctional buttons

USB-C-Input
(only VBUS, 1,44″ GND, CC1, CC2) Color Display

USB-A Port

(male)

BT status (changes by a connection from flashing light to a permanent light)

USB-C-Output (only VBUS, GND, CC1, CC2)

3. FUNCTION MENU AND NAVIGATION
General use

Measurement result main page

QuickCharge detection

Recording of charging process

Cable impedance

Measurement graph

System settings

Use

and

to switch between the separate

menu pages.

Hold

to switch to the next data group. Hold

to reset the current data group.

Language settings
To change the default language of your device, you must first disconnect your device from the power source. Now press and hold any multifunction button and reconnect the device. Keep the key pressed until your desired language is selected on the display.

Press to turn off the display
Hold to rotate the display counterclockwise

Hold to open the help menu
Press to rotate the display clockwise

Press for the previous page
Main menu (measurement results)

Press for the next page

Voltage
Current
Accumulated electrical loading
Accumulated energy

Temperature Data group Equivalent resistance Power consumption

The values of the data group 1 – 9 will be saved by a voltage interruption of the measuring device and is recalled and continues after the device is switched on again.
The values of data group 0, however, will be showed after the restart flashing and then it will be reset to 0 when 1mAh has been reached.

QuickCharge detection

Voltage of D+ (DP)

Mode indicator

Voltage of D- (DM)
The meter automatically recognizes devices with QuickCharge support. The following QuickCharge modes are currently supported: QC2.0. QC3.0, Apple 2.4 A / 2.1 A / 1 A / 0.5 A, Android DCP, Samsung
Recording of charging process

Accumulated electrical loading
Total accumulation time
Trigger current for recording

Accumulated energy
Recording indicator Red: Recording paused Green: Recording in process

After power is turned on, if the flowing current is greater than the trigger value, the system automatically starts recording the accumulated electrical charge, energy and elapsed time. The ,,REC” indicator then changes from red to green.

To set the current trigger value, press

and hold it to

highlight the value. Press

to adjust the value accordingly.

The value can be set anywhere between 0.01 A and 0.3 A.

Cable impedance

UM25C directly at the power supply system: Voltage and current values are displayed
UM25C via data connection: Voltage and current values are displayed

Resistance of the data connection cable

Measurement procedure: First, connect the measuring device directly to the source and set the corresponding current load (recommended value: 1 A). Press and hold the button to start data recording.

Now, disconnect the meter and then connect it to the power source via a

microUSB or type-C data input connection and set the load current to the

same value as in the first step. Press

and hold the button to

switch to the to begin data recording.

The display prompt stops flashing and the resistance measurement test of the data connection cable is completed and the value is displayed.

Attention! If the screen goes black in the second step, this means that the voltage difference is too high and the tester switches to the 4 V shutdown state. The load current must be reduced. Then restart the measurement from the first step. After the resistance test of the data connection cable is completed, the tester must be switched off and on again to continue the measurement.
Measurement graph

This menu displays the voltage measurement over time in the range of 4 – 24 V, as well as the current measurement in the range of 0 – 5 A and automatically adjusts the displayed range in real time to account the voltage and current fluctuations.

Press

and hold to switch D+ / D- graph. This interface

displays the D+ / D- voltage measurement over time in the range of

0 – 3.3 V and automatically adjusts the displayed range in real time to

account the D+ / D- voltage fluctuations.

System settings
Time until automatic screen shutdown (default 1 minute)
Display temperature (default Celsius)
Foreground color scheme ( default 6, white)

Screen brightness (default level 4)
Background color scheme (default 2, blue)

Press and hold the button

to enter the setting mode,

press

again to navigate through the options. Then press

to change a setting and press

again to

cycle through the setting options. At each setting state, press and hold

to exit the system settings.

4. PC – SOFTWARE
1. Connection
First download the software installation file here. Additionally, you need the font package Arial Unicode MS.ttf, this is located in the same folder as the installation file. Please install the font package first, before you continue with the installation of the software.
Now, install the software and follow the instructions there during the installation process.
After the installation process is completed, activate first of all the BT function on the UM25C measuring device with the BT switch. Then use the BT search in the settings of your computer to search for new BT devices. Add the UM25C device when it is found. If you are asked for a PIN during connection setup, please use the pin 1234 or 0000.

The screenshots shown here are from Windows, trademarks like Bluetooth or Windows belong to their respective owners.
In order to be able to connect the installed software to the measuring instrument, it is necessary to know which port is used, to connect the instrument to your computer. To do this, select in the BT connection overview BT settings. In the window that now opens, select the COM ports tab. The necessary interface in this case is UM25C`Port`.

2. Usage of the software
Now, open the UM25C PC software V1.3, which you have already installed on your computer. First, set the appropriate COM port to which the measuring device is connected to your computer and start the connection with the Connect button.

Basic functions

(previous page, next page, rotate screen)

Data groups

(direct selection of the data groups)

Main measuring interface

Data recording interface

QuickCharge interface

Temperature overview

Screen brightness,

Time for automatical image shut down

Voltage-current diagram

With a right click within the voltage-current diagram, further options are available. Here, you can automatically scale the x-axis, copy the current data to the clipboard or rather export it as an Excel file, export the current graph as an image or delete the current graph.

5. ANDROID APP
First download the app installation file here on your Android device and install the application.
Attention! The application can only be used with Android 5.0 or higher.
Activate BT with the BT button on the meter, then establish the connection to the meter using the BT settings on your device. Use either 0000 or 1234 as the PIN during connection.
After the installation and connection is complete, you can start the application.

Data export

Language settings

BT connection

General information

Voltage-current diagram

Accumulated mAh and mWh

QuickCharge detection,

D+ and D-

Data voltage signal

Brightness and

temperature adjustment

Go to the next page

Reset current

data group

Rotation of the display

Go to the previous page 12

Recording the charging

process

Main measured

values

6. OTHER INFORMATION

Our information and take-back obligations according to the Electrical and Electronic Equipment Act (ElektroG)
Symbol on electrical and electronic equipment: This crossed-out dustbin means that electrical and electronic appliances do not belong in the household waste. You must return the old appliances to a collection point. Before handing over waste batteries and accumulators that are not enclosed by waste equipment must be separated from it.

Return options: As an end user, you can return your old device (which essentially fulfills the same function as the new device purchased from us) free of charge for disposal when you purchase a new device. Small appliances with no external dimensions greater than 25 cm can be disposed of in normal household quantities independently of the purchase of a new appliance.

Possibility of return at our company location during opening hours: SIMAC Electronics GmbH, Pascalstr. 8, D-47506 Neukirchen-Vluyn, Germany

Possibility of return in your area: We will send you a parcel stamp with which you can return the device to us free of charge. Please contact us by e-mail at Service@joy-it.net or by telephone.

Information on packaging: If you do not have suitable packaging material or do not wish to use your own, please contact us and we will send you suitable packaging.

7. SUPPORT
If there are still any issues pending or problems arising after your purchase, we will support you by e-mail, telephone and with our ticket support system.
E-Mail: service@joy-it.net Ticket system: https://support.joy-it.net Telephone: +49 (0)2845 9360-50
For further information please visit our website: www.joy-it.net

Published: 2025.07.08

www.joy-it.net SIMAC Electronics GmbH Pascalstr. 8, 47506 Neukirchen-Vluyn

Documents / Resources

JOY it UM25C Measuring Device [pdf] User Guide
JT-UM25C, UM25C Measuring Device, UM25C, Measuring Device, Device

References

User Manual

JOY it UM25C Measuring Device User Guide

UM25C Measuring Device

Specifications:

Product Usage Instructions:

Function Menu and Navigation: