@ chartmaker:
although this is off-topic in this thread, some few hints.
-Try with test account first
-enter for Sip-Number, User-ID and User-Password the string "test"
-enter Sip Server Adress, RegistrationServer and SipDomain with "sip.sipdiscount.com"
-check all port numbers to be "5060"
-Extended setting try without or with STUN aktive
-Make sure not to use PPPoE if you have a router
-Make sure your router allows ports 5060 being open, may be try with "DMZ" on the router. Fritz Box Fon works without any port change.
-Make sure the telephone setting 1 and 2 are correct.
If you don't succeed, please open new thread with proper headline.
Chris
Edit: see also
here