I bought an x30 about a month ago; been playing with it daily and investigated its serial connection.
While there are a number of "homebrew" suggestions for serial cables out there, I decided not to risk my new PPC on an unproven solution and my soldering skills. I purchased an x30-to-serial cable from Supplynet:
http://www.thesupplynet.com/productD...fm?prodID=7313
It's clean, professional, and includes a DC adapter to use in the car that powers the x30. OK, so it's 50 bucks; what's it worth to you to not blow up your handheld?
One end is the Dell Axim connector; the other end is a DB9 female connector (just like on the back of your computer); in the middle is a bulge with the jack for the DC power cord. I run Mapopolis and cable it to my Magellan GPS315 and it works great.
BTW, I'm a 10-year Palm OS addict... my last Palm was a Tungsten C. The x30 is soooo good,three days after getting my x30 I sold the Tungsten on eBay.