If you have Caller ID you'll now know when the person trying to reach you is a telemarketer.
Federal Trade Commission regulations requiring telemarketing firms to identify themselves take effect today.
Such calls had shown up on Caller ID as "out of area." But now the name displayed must either be the company trying to make a sale or the firm making the call.
The display must also include a phone number that consumers can call during regular business hours to ask that the company stop calling them.
The change is part of the rules that set up the do-not-call registry, which consumers can use to block certain telemarketers from calling.
More than 56 million phone numbers are now on the do-not-call list.