Monday, December 27, 2010

Incommunicado

I have spent a frustrating couple of hours trying to make a PC cable to communicate with the VX-8GR. In the VX-8 Yahoo group it was stated that the cable is the same as for the Kenwood TH-D7AG a diagram of which is given in YO3HJV's blog. It was also pointed out to me that there is a diagram in the back of the manual - the one place I never thought to look!


It is easy enough to make up. No level shifting components needed. Just a 2.5mm stereo jack for the radio end and a 9-pin D plug for the PC end. But the damn thing refuses to work.

I have tried a Prolific USB to serial adapter and an FTDI one. I've tried the FTBVX8G software and I've tried a terminal program to see if I can detect any data. Nothing. Nada. Incommunicado. I know the cable is OK because if I short between tip and ring of the jack plug I can type in the terminal program and see the text I typed echoed back over the connection.

The only thing I can think of is that the standard 2.5mm stereo plugs I have here are a bit too short. It seems to me that the  plug isn't locking firmly into place, more that the radio is trying to push it back out again. It's as if the tip needs to be a bit longer to get past the spring loaded contact in the socket. I measure 7/16in from the base of the plug to the tip of it. I had a similar problem trying to make a cable to send audio from my FoxTrak APRS tracker into my Motorola GP300. Then I had a plug from a speaker mic to compare it with and I could see that it needed to be longer.

Perhaps someone who has a VX-8G PC cable that works could measure the plug on theirs. Or perhaps someone will spot the stupid wiring mistake I've made from the photo I've posted.

8 comments:

PE4BAS, Bas said...

Hello Julian, could the picture of the D-SUB 9 pin be from the solder side. I can't read anything that the picture is from the front side? Just thinking?? 73, Bas

Julian said...

Hello Bas. I thought someone would say that. No, it's from the front. You can't see from the photo but the pin numbers are embossed into the blue plastic so the green wire from the tip of the jack does go to pin 2.

skids said...

Hi Julian, I notice on YO3HJV'S diagram that pins 1&4 are connected together. That’s what it looks like to me.

Chris G0BHX

Julian said...

Hi Chris. I had them connected originally. It didn't work. Then I was directed to the diagram in the manual which didn't have them connected, so I removed the link. It still didn't work. :(

Ken said...

How about trying it with the D72?

skids said...

You might be right about the 2.5mm plug. Yaesu do seem to use non-standard connectors at times.

Hope you sort it….Chris

Julian said...

Ken, I hadn't realized the D72 had a (non-USB) COM port. Having ascertained that it does, and that it uses an apparently compatible connector, I tried to get something out of it, but it doesn't seem to be possible to access the TNC through it. The only output option for the COM port appears to be Waypoint, but I couldn't get anything to appear there. However when cycling through the TNC options I discovered that "CR/LF GPS CR/LF" is output to the port (at 4800 baud regardless of the menu speed setting) which at least seems to show that my cable is OK.

George Smart said...

I'm pretty sure it's the 2.5mm plug not being long enough. I have a break-out cable (CT-92) for the audio/mic connections for mine and it's shorter than the standard 4-ring connector. I suspect this is what they've done...

George, M1GEO.