Hi,
I have been using a radio for the last 6 years or so when flying a paraglider up in the mountains. I need very little from a handset, only VHF and for it to be light, robust and simple to use but the one thing I do need is hands-free kits. I have to control the wing at all times. I had an accident in Mexico recently fiddling with a radio at cloud base having taken my hands off the controls. I have a PTT, mic and earpiece all attached with a long cable that goes down my arm to my hand and up to my helmet. I also have a Blue Tooth unit that will be a big improvement but I've yet to install it, or I held off on installing it as I had decided to purchase a new radio. The radio of choice amongst the paragliding community is the Baofeng for obvious reasons and I've had two of these, maybe three, I can't recall but they have all been unreliable in different ways so I decided to go for a reputable make this time and bought the Yaesu FT-4V. This unit seemed perfect for my use but upon receiving it I found that what I thought was a universal connection for the accessories is actually not, the 3.5mm and 2.5mm jack dual plug has the position of the two jacks spaced slightly differently so the hands-free stuff I have will not fit. This was annoying and when I looked up the FT-4V accessories was even more annoyed to find they had designed it so I could only use their equipment and not even bothered to make any available.
So I asked on this forum and one person suggested that it would be pretty easy to just solder a new plug, I know Ham radio enthusiast can be pretty proficient with electrical engineering and I took this with caution but I can solder equipment together for my audio kit so I'm not a complete novice. I stripped the plugs to see exactly how everything is connected and rebuilt it with two independent, narrow 3.5 and 2.5 jacks so my hands-free kit would fit any radio but when I plugged it in it was wrong, stuck on transmit with no audio coming through. I checked it on the Baofeng and it was wired right. So Yaesu is using different connections. I set up a little test bench and cycled through every possible connection of the four wires and six connections on the plugs, Though I kept the 3.5mm connection to the 3.5 socket and vice versa. Nothing worked. The closest I got was continual transmitting with no audio and transmission with the PTT but no audio coming through.

I've given up for now. I'm going away for a month or so flying next week and will have to choose the crappy range of the Baofeng or the more reliable Yaesu that I'll have to use with my hands and look at what to do when I return but then I thought I'd come here and see if anyone has been down this road before and has any advise.