Just my 2 cents, but I use the SignaLink USB interface. Considerations in its choice:
1. Cost -- $99 from DX engineering. Mine was back ordered at that time, but showed up in 3 weeks. 2. Included the interface cable for my FT-817ND in that price. If I want to run another rig, I'll simply get another interface, though cables and the header block for the jumpers are available separately. 3. Gets power from the computer (I use an Acer Aspire One with Windows XP) 4. EASY setup -- just set the jumpers. Major problem was finding my good tweezers and a hemostat to push in the jumpers. I am at the tri-focal stage of my life. 5. Documentation in clear, and in PDF form -- I keep it on the Acer for quick reference. 6. The "PTT" problem is nil, as the card senses a signal and activates the PTT on the FT-817ND. 7. I marked the proper settings for the levels and delay with a small dot of white paint. Haven't had to change them. 8. Works perfectly with JT65HF, wsprnet, HRD/DM780, MMSSTV, Fldigi, Spectran (just for monitoring), etc., etc. ONLY problem I have found that some software doesn't allow you to properly select the sound card... mostly older stuff. However, a "work around" is to disable the default sound card, turn all sounds "off," and this presents the SignaLink as the ONLY sound card seen by the software. Separate control cable is needed for HRD to FT-817ND. As my net book has only USB connectors, I made it a point to get the interface cable that "fakes" an RS-232 connection, which is what the FT-817ND presents to the outside world. This is quite a separate issue from the SignaLink interface. I have been using it for 18 months now with nary a problem. /paul W3FIS
