If you want a really clean installation for PSK-31 as well as the other digital modes that make use of a sound card the TigerTronics SignaLink USB is a great way to go. Just two cables to connect, a USB cable from your computer to the SignaLink USB and a purpose built cable (included) to connect to the the radio. I have the Kenwood cable for my TS-2000 and will be making a custom cable to use it with my Small Wonders PSK-20 transceiver. A big plus for this devise is that you are not using your computer's internal sound card.
The SignaLink USB uses the audio stream to trigger the radio's PTT. After some initial confusion over this we got it working this past weekend. The signal it generates is very clean (back off the audio drive to your transmitter so that the ALC shows zero) and it decodes very well.
The SignalLink USB has gotten great reviews at eHam:
http://www.eham.net/reviews/detail/7113
Here is the TigerTronics website where you can learn more about their SignaLink USB and their other products:
http://www.tigertronics.com/
Tigergronics Signalink USB--packet problems
I have no experience with HF use of the Signalink USB, but I borrowed one to try out packet transmissions on the 2M band. I want to use the Airmail program for email and direct computer-to-computer connections, which is what the ARES/RACES nets use. But the Airmail program is not set up to handle this type (i.e., sound card) of TNC, and although there is a purported work-around, I have yet to get it to work. So if you are interested in 2M packet, the recommended TNC seems to be the Kantronics models. However, if you already have a Signalink USB device, and are interested in trying to make it work with packet, let me know and we can work on it together!
Tigergronics Signalink USB--packet problems
Airmail was set up to primarily run with a TNC. The reason was that PACTOR is the mode WinLink is using and Airmail was set up to support this service and Sailmail, the commercial version of Winlink.
Winlink was established to support e-mail over HF for RV'ers and cruising sailors. This began to compete with the shore stations so someone started sailmail which is a subscription service for those who could not use the ham bands but had a marine radio license and station.
Pactor I was used because it is a connection oriented mode with reasonable thruput. SCS, a German communications firm, invented the mode and published it for use by hams. That is why TNC's like the KAM can do PACTOR; however, Pactor II and III are maintained as a proprietary mode and can only be used with SCS modems. Pactor III is very close to the state-of-the-art with waveforms over HF. I suspect that Winlink will stay with Pactor because of this.
There are a number of bright hams pushing MIL-STD-188-110 or 141 HF ALE as a hail preceding Pactor. This will improve the probability of a connect on a good frequecy. This will add to the argument by the Winlink folk to continue on the path they have chosen.
ARES/RACES may be out of step with what the MARS program is doing. MARS has a variant of ALE that looks like it will work with Winlink. You may want to do a little looking into all of what is happening on HF. Some of it is gee whiz and is being adopted by a number of hams and EOC operations in the country.
73,
Barry
K3NDM