Simply power the system up. Green light should come on.
If you have a display set plug in in to x10, test for dial tone on CO line's 1 and 2. Listen to see if it is clear.
Make sure all the buttons work. Test each port for CO and intercom dial tone. Set the time and date, leave the system powered up 8-10 hours. Power down, wait about 30 minutes then power it back up. Did it save time and date? Test that all ports on 206 are still working.