Firmware update information
Last updated : May 17, 2017

The TH-D74A/E firmware has been updated from Version 1.05 to Version 1.06 as follows.
We are offering the firmware updating program to the TH-D74A/E owners.
You can update the TH-D74A/E firmware by connecting the TH-D74A/E to the PC by using a Micro-USB cable.

About virtual COM port driver for the TH-D74A/E

A virtual COM port driver needs to be installed onto the PC to use the firmware updating program with a Micro-USB cable.
ATTENTION:Do not connect the transceiver to a PC using a Micro-USB cable before installing the virtual COM port driver.

Updated items : (Version 1.05 1.06) [May 17, 2017]

Updates the following feature.

1. Enables copying positional information from "Position Memory" to "APRS Object" as well as to "My Position".

Press [MARK] and select a stored Position Memory (0-99) as the copy source, and press [ENT] to display the selected Position Memory's details screen. Next, press [A/B] and select "Copy to APRS Object", and press [A/B] to select an Object (1-3) as the copy target. Then selected Object's details screen will appear, and press [A/B] to copy the information (Name, Position, Icon) from "Position Memory" to "APRS Object". Please edit other Object settings in Menu No.516 (APRS Object).

Revises the following symptoms.

1. Cannot copy the CALL Channel's memory name to the Priority Channel.

2. The radio might reset automatically when sorting APRS Station List.

3. In KISS mode, the special character 0xC0 (FEND) is not converted correctly.

4. In KISS mode, outstanding TX data might not be sent correctly after STA icon goes off.

5. In Memory Channel mode, stored D-STAR repeater's information might not be indicated correctly.

6. After sending an APRS beacon in data band, the busy indicator in non-data band disappears.

Updated items : (Version 1.04 1.05) [December 21, 2016]

Updates the following features.

1. When displaying details of the APRS station's data (Page1/4~Page4/4), the D-STAR station's callsign under reception appears in the one line display area as well as the APRS station's callsign.

When Menu No.612 (Direct Reply) is set to "On" (default), D-STAR stations' callsigns appear preferentially than APRS stations' callsigns. And when the Direct Reply operation is available, "*" appears at the right side of the D-STAR station's callsign.

2. QSO history on the same date is stored in the same QSO Log file created by each date.

3. Improves Squelch characteristics in a high-noise environment.

Revises the following symptom.
1. When pressing [F] while the D-STAR Repeater Information or D-STAR RX History Position data is displayed, the North Up / Heading Up does not change correctly.

Updated items : (Version 1.03 1.04) [October 31, 2016]

Revises the following symptoms.

1. In DV/DR mode, TX/RX function might become unstable.

2. In DV/DR mode, NMEA sentences (GPS data) are not transmitted correctly.

3. In DV/DR mode, "ATT" indicator is not displayed.

4. In DR mode, unnecessary error indication appears when using Reflector menu functions.

5. Memory Scan may not work correctly under certain conditions.

6. Cannot recall locked-out memory channels from the memory channel list.

Updated items : (Version 1.02 1.03) [September 30, 2016]

Updates the following feature.

1. Supports some DV node devices' irregular data formats.

Revises the following symptoms.

1. The "Mic-E Type Code" in an APRS beacon may not be sent correctly under specific settings.

2. In AM/SSB/CW mode, squelch function might not work correctly.

Updated items : (Version 1.01 1.02) [September 16, 2016]

Revises the following symptoms.

1. APRS popup screen may not appear correctly under certain conditions.

2. In DR mode, current access repeater might not be backed up when turning the transceiver OFF.

Updated items : (Version 1.00 1.01) [September 7, 2016]

Revises the following symptoms.

1. In DV/DR mode, RX History may not be stored correctly.

2. In DV/DR mode, receiving audio might not be recorded.

Applicable models/units :

The firmware updating program is applicable for the following models/units.

Models: TH-D74A, TH-D74E
Serial numbers: From S/NO.B68xxxxx through S/NO.B75xxxxx approx.

Notes: You can find the serial number imprinted on the rear panel after removing the battery.; It consists of an 8-digit number beginning with "S/NO."

You can check the firmware version of your TH-D74A/E by accessing Menu No.991.
The firmware version appears in the LCD display.

Operating Environments

1. Operating System (OS)

Windows® 7 (SP1 or later) (32-bit or 64-bit)
Windows® 8.1 (RTM or later) (32-bit or 64-bit)
Windows® 10 (Version 1511 (OS Build 10586.0) or later) (32-bit or 64-bit)


This software is designed to run on the above operating systems.

Applicable operating systems are subject to change without notice due to the end of the technical support by Microsoft Corporation or change of the product specifications.

The .NET Framework 4.6 which is available for download from Microsoft download center must also be installed. (Windows® 10 users do not need to install the .NET Framework.).

2. Processor

Faster than the recommended CPU for each OS.

3. System Memory (RAM)

Larger than the recommended System Memory for each OS.

4. Free Hard Drive Space

Larger than the system Hard Drive Space for each OS.

5. Peripheral Devices

A display with resolutions higher than VGA (640 x 480)

A keyboard and a mouse, or other pointing devices.

USB 2.0 interface.


If you do not want to lose user data, save the data using the Memory Control Program MCP-D74 before updating the firmware and write the data back after updating the firmware.

Turn the transceiver OFF before connecting it to a PC.

You cannot connect the TH-D74A/E to a PC COM port via an RS-232C cable.

Notes on usage

Users are required to obtain an approval from JVC KENWOOD Corporation, in writing, prior to redistributing this software on a personal web page or packet radio.

Users are prohibited to assign, rent, lease, or resell the software.

Users are prohibited to revise, change, translate, merge, de-compile, or reverse engineer the software.

JVC KENWOOD Corporation does not warrant that quality and functions of this software comply with each user's purpose of use of this software, and unless specifically described in this document, JVC KENWOOD Corporation shall be free from any responsibilities to any defects and indemnities to any damages or losses. Selection and installation of this software shall be done by the user's own designation. The user shall take full responsibility for the use and effects of this software.

JVC KENWOOD Corporation shall be free from any responsibilities for any incidental losses or damages, such as missing communications or a call opportunity, caused by a failure or performance error of this software.

JVC KENWOOD Corporation shall own all copyrights and other intellectual properties for the software and all manuals and documents attached to the software. The user shall be allowed to use, not to resell, the software by obtaining a license from JVC KENWOOD Corporation. While the media on which the software is stored is possessed by the user, the ownership for the software itself shall be reserved for JVC KENWOOD Corporation.


Extract the downloaded file "" into a designated folder.
In the designated folder, a folder labeled "TH-D74_V106E" will be created.
In the folder labeled "TH-D74_V106E", two files "TH-D74_V106_e.exe" and "TH-D74_e.chm" are automatically created.


1) Start the program by double-clicking "TH-D74_V106_e.exe" icon.

2) Connect the transceiver's USB port to your PC's USB port using a Micro-USB cable, and select the COM port you will use by following the Help file.

3) Proceed firmware updating by following the explanations in the dialog boxes.


Delete the folder labeled "TH-D74_V106E" manually using the Explorer or an alternative method.
This software does not modify the system registry parameters or system folder.

If you agree with the details listed above, click the following link to download the firmware updating program.

(The latest version includes all previous updates.)

TH-D74 Firmware Update Version 1.06 (May/ 2017) : 7.36MB download

Windows is a registered trademark or trademark of Microsoft Corporation in the United States and other countries.

.NET Framework is a registered trademark or trademark of Microsoft Corporation in the United States and other countries.