S/PDIF stands for "Sony - Philips Digital Interface".  It was originally
designed in the early 1980's for home CD players and DAT recorders. 
(Sony and Philips are the two companies that developed the CD Audio format.)

S/PDIF allows a digital audio recorder (such as a DAT machine) to receive
audio as binary data from a digital audio player (such as a CD player).  
By sending and receiving the audio as binary data, it's possible to transfer
the audio with perfect fidelity to the original source, with no tape hiss or
hum added. 

Digital audio recorders are quite common nowadays.  Your PC's soundcard is 
a digital audio recorder, and many people have DAT and MiniDisc recorders.   
Also, many computer users have CD-recordable drives, which can be used 
to make audio CDs that can be played on standard home CD players. 

Whether you're a musician who wants to make a homemade CD, or a bird-
watcher who wants to save your collection of birdcalls on a CD, or a 
parent who wants to record your child's first words, you can capture the 
sounds on a portable MiniDisc or DAT machine with very high-quality. 

But how do you make a great sounding CD from this? 

Assuming that you have a suitable CD-recordable drive in your computer, 
you will first need to get the sound on to your computer's hard drive. 
There are two ways to do this: 

1) ANALOG TRANSFER
   You can connect a suitable cable from your recorder's Line Out jack to 
   the Line In jack on your soundcard.  You will need to set the levels 
   manually in your computer's recording software.  If you set the levels 
   too low, you will get too much hiss and noise.  If you set the levels 
   too high, the recording will be distorted from signal overload. 

2) DIGITAL TRANSFER
   If you have S/PDIF connectors on both your recorder and your soundcard, 
   you can easily make perfect audio transfers every time.  Just connect a 
   suitable cable from the S/PDIF Out jack on your recorder to the S/PDIF In 
   jack on your soundcard.  Activate the Digital Audio I/O in your audio 
   recording software and you're ready to go. 

Once the audio is on your hard drive as a wave file (.WAV) you can edit it,
add effects, make it louder or softer, and finally change it to 16-bit 
44.1 kHz format for burning to CD. 

*** IMPORTANT NOTICE *** 
The Fiji and Pinnacle with digital I/O have coaxial (RCA) S/PDIF connectors
and are designed to automatically synchronize ("slave") to an external word
clock source.  Typically, pro-quality digital audio gear will send this word
clock data when initiating a S/PDIF transfer.  Many less expensive, consumer-
level DAT and MiniDisc recorders lack this capability. 

For more details, see the article "S/PDIF - how to use".

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