Hi Roy,
No, you cannot connect the organ directly to your computer. You must have an Audio Interface in between. Brian has the Behringer UCA 222 and I have the Behringer UCA 202. Both do the same. The only difference is their colour. The 222 is red and the 202 is silver. The UCA 202 (or 222) has a permanent lead to plug into the USB Port of the computer (ie. it is not removable). This lead provides the power for the UCA 202 as well as providing the Stereo Input for Audacity. The UCA 202 (or 222) has a green light which lights up when it is powered up.
The Behringer UCA222The Behringer UCA202The lead you have to buy is a Stereo one from your organ to the UCA 202. Your organ will have a LINE OUT, and if not you can connect from your headphone socket. So the plugs you need at the organ end only you can decide.
The UCA 202 (or 222) has an INPUT for RCA plugs, as Brian says. These are also known as PHONO PLUGS. Take a look at the Amazon picture for this device. You will see quite clearly what the sockets look like.
These are what my RCA (PHONO) Plugs look like:
One plug is white and one is red (the yellow one in the picture is for video .. my lead doesn't have a yellow plug). The RED plug is for the right channel and the WHITE one for left channel.
Please note that there are also RCA (PHONO)
OUTPUT sockets on the UCA 202/222,
but these are not used as the output lead we use is the fixed one attached with the USB plug on the end.
Hugh