A JR trainer cord is very simple... just a couple mini plugs and an appropriate length of 2 lead stranded wire(like servo wire). Solder the leads to the same terminal lugs on the each mini plugs and go use it. I made mine because I lost the original and I am too cheap to spend even $10 on a factory cord. I cannot coment on making trainer cords for other brands, but JR is simple enough for even a novice to build. I have used mine hundreds of times without a single problem. Good luck!

Dan