If I was to block a person's phone number would they still be able to get through by caller ID spoofing?

Question

I have to reason to believe that persons very close to my family has been trying fraud us by forgering there number to look like debt collectors. I have block these persons numbers and the calls stop. When I unblock them we received them again. Could this be the case and could I be strumbling on something even bigger involving quite possibily a nation wide money scam?

Answer 1

Many large companies use what is called a PBX system (PUBLIC BRANCH EXCHANGE) such as a Northern Telecom Option 11 or Avaya IP Office.  Those systems are generally backed with several T1 lines (digital lines that are comprised of 23B and 1D channel allowing 23 in and out bound calls over 2 wires).   When using a PBX system, in most cases, it can outpulse whatever caller ID the company programs into their system, bypassing the phone company switches caller ID.  This is why you will see any numbers come up like 000-000-0000 or you will get a number that when you call it back is disconnected, or you may get something line 0040.  The point is, If alot of people block a telemarketers number, they can always change the number that's sent out to your caller ID and get past the block since they are sending  a new number that you have not blocked.