COM Port Setup - Quick tutorial

A few years ago, I publish a cable diagram for Kenwood TH D7, the little APRS dual band radio.I received some questions about the next step in conecting the radio to a PC, the COM Port setup.
So, I did a little video tutorial for this.
The most tricky part is to have a low COM Port number in order to connect to the PC. Most of the software in the market (or available to the Ham community) ask for a low COM number (COM1 to COM9) some of them only to COM6 so, after some time of computer use with a lot of USB devices, the DEVICE MANAGER (XP) will add ports and is common to have a COM25 or COM34 listed instead a convenient COM2 or COM4.
So, a little trick is necessary and this is my video about.



 You have to ignore the warnings about the malfunction when changing the COM number but you have to remember that the COM assignement is linked to the USB in which the COM2USB is plugged. So, you will have to repeat the setup for all the USB ports in which you put the adapter.

If you have questions, please leave a comment.

73 de Adrian

TH-D7 PG-4W programming cable diagram

Well, I just received a very nice Kenwood TH-D7G(II) portable VHF/UHF radio.

The main problem was the programming of my favourites frequencies. I started to grab informations from the internet regarding the software I need and, most important, what cable to use.
The internet is very poor in informations about PG-4W, the programming cable, but there are a lot of vendors (from 12 to 25 EUR/cable) which is quite inacceptable for me... I do know how to make a PC to Radio cable!
So, I prepared myself with a RS232<>TTL adapter (with MAX232), one 2,5mm stereo jack and some lenght of cable, a female DB9 COM port and some patience...
First step was to read carefully the User manual where it states that the radio conect directly to the PC.

To be sure I was measuring the voltage on the PC conector at the radio.
It was -6V (RS232 zero logic level) which means the radio has a RS232<>TTL level adapter inside. So, indeed, tha radio connect directly to the PC Com port...
I made the connections, but the software returns (over and over...) a communication error (Timeout).
So, I started to search for a reason. Maybe the software expect some signaling on the other ports of the COM...
I realise that, when I push the "Read Radio" command on PC, on the COM port RTS appeared a voltage swing. Hmmmm..... so, the Radio <> PC cable is not so simple...
So I connected the RTS with CTS and DCD with DTR and, BINGO!!!!, all was OK!
So, here is the diagram of the PG-4W programming cable for the Kenwood TH-D7 portable radio...

 Later Edit: Tom, NV1U sent me the following diagram made on his tablet:

 TNX Tom!


!!!!!!!!!!!!!WARNING!!!!!!!!!!!!!!!
There is NO ERROR!!! The 2,5 mm plug diagram is not reverted!!!
The manual states that the tip is TxD and the ring is RxD. The TxD and the RxD on the plug ARE FROM THE RADIO VIEW
The radio transmit data to the PC by the tip of the plug and the signal goes to the RxD on COM port at the PC!

For programming the radio I use a IBM X61T with a USB<>COM adapter and the MCP-D7G, ver.1.01.