Random call from Pittsburgh...
We have had the 412 area code blocked for over 1 year.  
ANY and all calls coming from the "412" are blocked thanks to our Di** tone call blocker.
When you block and entire area code, you block 6,000,000 - 8,000,000 million phone numbers.
Have friends or relatives in the 412 - no prob - simply add their numbers to your "invite" list.  Problem solved.
Please purchase a call blocking device that can block entire area codes along with individual phone numbers.
We have nearly 200 area codes blocked - Sweet!