For the second time in three months, the Federal Communications Commission (FCC) has walloped a telecom for making unwanted telephone calls to consumers. Last week, the FCC fined Primus Telecom (NASDAQ:PRTL) $400,000 for violating a circa-1992 predecessor list to the famous National Do Not Call Registry (DNC Registry) that the Federal Trade Commission (FTC) set up in September 2003.

The first and most famous instance of presumed FCC enforcement of the FTC's DNC Registry (even without all the alphabet-soup names, the similarity in purposes between the old do-not-call list and the new DNC Registry confuses many consumers) took place in July of this year, when the FCC finally settled a similar charge it had pursued against AT&T (NYSE:T) since November 2003. AT&T got hit with a larger fine than did Primus ($490,000) but actually got off easy. The FCC had alleged that AT&T made a total of 78 unsolicited phone calls to 29 complainants. At a maximum of $10,000 per violation, AT&T could have been fined $780,000.

The most interesting fact about each of these FCC enforcement actions is that neither one was based on the relatively famous DNC Registry, which since October 2003 has forbade all unsolicited telemarketing to the 60 million-plus consumers on its list. Rather, both enforcement actions were based on the 1992 do-not-call list created under the Telephone Consumer Protection Act, which forbade only telemarketers who had been specifically asked not to call from calling the specific consumer who asked them not to call.

To date, however, the much more ballyhooed DNC Registry has not been the subject of a single FCC enforcement action. While several states have reached settlements with offenders against the newer federal law, the Feds themselves are still sitting this one out. Why? I have no idea -- but I'd love to hear the thoughts of any Fool out there who does. Give this link a click and clue me in if you know: I know why!

For more Foolish information on the DNC Registry -- and how to sign up, read:

Fool contributor Rich Smith owns no shares in any company mentioned in this article.