I was considering getting a nx-5000 portable for amateur use, and I have an ftdi cable that would hopefully work. I saw somewhere that the ftdi cables work, but can take up to 4 minutes on the newer models. I don't care how long it takes as long as it works.
One like this: FTDI USB Programming Cable for Kenwood NX-5200 NX-5300 NX-5400 TK-490 as KPG-36 | eBay
One like this: FTDI USB Programming Cable for Kenwood NX-5200 NX-5300 NX-5400 TK-490 as KPG-36 | eBay