I have an old STS AV7600VOR handheld radio, which is as good as new. STS are long out of business, I hear. I can find new batteries, no problem, but I can't seem to find an adapter that would let me plug my headset into the weird 6-pin plug it has. Anybody know where such a thing might be found? Searching the net, i am not the only one looking, but I found no answers.