Build your Kenwood KPG-46 cable using USB UART converter CH340

Yes, It will work in CHIRP without the need for you to use the Kenwood proprietary software.

I recently needed to program a Kenwood Radio TK-8102H , after searching the internet I found out that the software required to program it is KPG-70D and the required interface is KPG-46 using RS232 logic level to TTL, either using D-subconnector (25-pin) or DB-9 serial.

After referencing several schematics for Kenwood programming cable, I found out that the IC commonly use is a MAX232 which requires a 5V power supply to operate. This requirement is fine when using old desktop computer which normally has a parallel printer port and a serial connector. For most modern computers the printer ports are usually replaced with a much efficient less complicated wiring USB connectors.

KPG-46 Programming cable Schematic

Kenwood Interface by: Craig Clark N5XNQ

Since I am using a laptop with no parallel and serial interface, I need to have a cable that can be plugged to my USB port. So I came across a datasheet for CH340, which can be used as a substitute for MAX232 ic.

CH340 Datasheet

Download the PDF Document here

Looking around I really don’t need to build it from scratch (sourcing the IC and components), it’s readily available on most online shops. So to make my life easier I just bought one for this project.

So looking back at the schematics for KPG-46, we just need to use the RXD, TXD, and GND pin when using the CH340 interface. One caveat, some of the available board for the ready made CH340 USB UART chip have wrong label for the TXD, and RXD pin, but no worries we just need to reverse the TXD and RXD pin to make it work like in my case.

So I happily make two programming interface one for HT (Works fine with China Radios) and for Kenwood TK-8102H

Programming Interface for HT (Kenwood and Baofengs)
Programming interface for HT Kenwood and Baofengs

To work with Baofeng here’s the pinout from Miklor site

And another one for the device that I need to program Kenwood TK-8102H

To make it work we need to install the driver for this chip CH34x_Windows Driver

When installed properly you’ll find it on your device manager in Windows under the Ports (COM& LPT) labelled USB-SERIAL CH340 and the com port where it’s accessible.

Let’s see it in action, when reading, the LED indicator will blink:

Reading the Kenwood TK-8102H Radio

Video from screen recording while reading the Kenwood TK-8102H

Reading the Baofeng UV-5R (aka Cignus UV85)

Video from screen recording while reading the Baofeng UV-5R

4 Replies to “Build your Kenwood KPG-46 cable using USB UART converter CH340”

  1. Hi; This is great! Quick question. Can make an adapter for a Baofeng UV-5R programming cable (that uses the CH340 IC) to use it with my Kenwood? If so what would the pinout be in the 8 pin connector? In your post you mention that only the RXD, TXD, and Ground is needed for the Kenwood, and I see where those are on my output on the Baofeng. What pins do those three connections go to in the 8 pin connector?

    Thanks, and 73

    1. Hi @ Robert, look at the KPG46 Schematic above – download the Max232 datasheet only pin 9 and 10 are used which corresponds to T2IN and R2OUT respectively TX/RX – connected to RJ45 on pin 2 coming from Max232 its from pin 9 (R2OUT), and on pin 5 on RJ45 its from Max232 pin 10 (T2IN), pin 4 on RJ45 connects to ground, and pin7 is from 5 volt regulator IC out. So you just need to play with pins corresponding to TX/RX on CH340. Perhaps this diagram would make it clear. <<< image is from ignore the connection on the left from the schematic since we are using USB to TTL converter we are only concerned with the pin out.

  2. Please I need your help, I have exactly that TK-8102 radio and I need to use the KCT-39 output, but I don’t know how to program the radio, I need help please

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