I called them, 800-270-2378.
Nice people.
The cable they sell for $25 connects a XM or Sirius tuner via their RCA conn to the aux input of a CDR 220.
Its a direct plug n play.
You can only use it if you do NOT have a CD changer however, as it uses the aux input.
Perhaps a switch can be fitted to have both.
Now I am looking for a CDR 220 at a reasonable price.
I will let you all know how I make out.
Cheers.
Len