Adding a 3.5 mm jack to your Treo 600
Well I finally got a hold of a working Treo 600 and I was able to perform the 3.5 mm antenna jack hack, just like I did on the Treo 650. It works great and you can even use your 3.5 mm stereo headphones on a call using the internal mic.
It was easier to place the jack in the antenna, but unlike the 650, I had to disable the existing switch in the 2.5 mm jack and use a 3.5 mm jack with a switch. The existing jack was broken so no big deal, but if it had been functioning properly I would have wired the switch in series with the new jack so that the existing jack would continue to function.
I won't be doing a how-to for this. Anyone with the right knowledge to perform this hack can figure it out using the instructions for the Treo 650. You just need to run 1 extra wire for the switch, which is for the right channel, or middle pole. I don't have a recommendation for a jack since I used a 4 pole and disabled the forth pole.
Hope you guys find it useful...