From PhatHack Wiki

[edit] Definition

The LG5350 USB Cable is a USB->Serial cable that uses TTL rather than RS232 levels on the serial end, this makes it useful for connecting devices such as the PhatBox

[edit] Where to buy

You can often obtain the cable from Radio Shack (PN 170-0783 above UPC, I got it for just $10 on clearance) or you can order it from: the FutureDial website

Please note, there appears to be another adaptor available for the LG5350 that is not a USB->Serial cable... make sure you get the one with the big bulge in the middle of the cable. If one is not available for a LG5350 you should be able to use any other USB->Cell cable with the bulge.