This page is not intended as a complete tutorial covering all facets of PSK station configuration. Instead, it is intended to be a quick overview providing links to other resources. It presumes you understand PSK operation at a basic level, consistent with the Ø7Ø Club's Intro to PSK page.
The classic PSK hardware configuration is a computer with sound card, an SSB transceiver, and an interface between the two (for audio signals and sometimes Push-To-Talk or PTT).
Virtually any SSB transceiver (or transmitter/receiver pair) can operate PSK if it has adequate frequency stability. Since the PSK signal is only 31 Hz wide, radios that drift more than a few Hz will be hard to track.
One generalization is that if your radio has DATA input/outputs, you are probably better off using them than using the MIC input and SPKR output. Not only can you leave your mic and speaker connected, but there are usually different gain settings for the DATA input (allowing you to keep the MIC gain set for your mic, and the DATA gain set for the computer's output), and the MIC input is often disabled when DATA PTT is selected (so your mic doesn't transmit room noises along with your PSK signal).
Small Wonder Labs has developed a series of PSK-only transceivers. Kits have been available for 80, 40, 30,20 and 10 Meters. Check with SWL regarding current availability.
The basic requirement for a computer is sound input/output connections and the ability to run the software you want to run. Each software package has its own minimum requirements - refer to the web sites for each individual software package for its minimum configuration.
PTT operation can be handled in multiple ways. It's possible to use your radio's VOX circuits in some cases. The "classic" approach has been having the software trigger the RTS or DTR line on a conventional serial (COM) port, and using this to activate PTT. It's also possible to use a USB connection, though some software is not configured for this. And some software can use CAT commands, using an existing serial (or USB) connection between the computer and radio that you have for rig control. You'll have to figure out what works for your exact hardware/software combination, but be advised that some combinations may require a conventional serial port.
Milt, W8NUE, has developed an alternative to a computer. The NUE-PSK digital modem is a self-contained interface and modem, requiring only an external keyboard. More details are available on this kit from the AMQRP web site.
Some PDAs may have enough processing power and audio in/out capability to run PSK software. One of the more impressive demonstrations of this was Ken, WI7B's use of an AT&T Tilt cell phone as described on eHam.
There are lots of interfaces available - I won't try to describe the pros and cons of each. Some work better for some radios that others. Some preserve the MIC and SPKR connections, while others usurp them. Some have built-in VOX, or accept USB inputs, or even include a sound card (so they don't take over your computer's). This is just a list of ones that I have seen mentioned (in a positive way) recently.
There are lots of DIY examples you can find if you Google the phrase "PSK interface". If you want to homebrew your own, a good place to start is Ernie, WM2U's web page.
A number of "signal monitors" are available that purport to help you keep your PSK signal adjusted properly. Some people swear by them, others swear at them. Here's a list without commentary, so you can form your own judgments.
There are many PSK software packages available. Many of the Windows packages use the PSKCORE.DLL "PSK engine" developed by Moe, AE4JY. Most of the differences are in the user interfaces, the "look and feel" of the packages. Many are freeware, some are shareware. Try out a few and make your decision.
DM780 (part of the Ham Radio Deluxe package)
WinPSK (mostly a prototype of how to use PSKCORE.DLL)
WinWarbler (part of the DX Labs Suite)
Zakanaka (part of the Logger32 family)
Many thanks to Steve, W3HF, for this page.