For Google, traffic pumping was unbearably maddening. The company decided in August to block Google Voice calls to destinations that had high call volume and a small population. One of the numbers blocked is for a free conference call service based in Redfield, S.D. Northern Valley Communications, the local phone company that handles that number, is in a legal battle with long-distance carriers that have refused to pay access fees to companies they accuse of traffic pumping. “‘Traffic pumping’ is a term fabricated by long-distance carriers who are trying to paint us negatively because we have higher access rates,” said James Groft, C.E.O. of Northern Valley.

Most rural phone companies are older, “incumbent” local carriers and participate in the payments system managed by the National Exchange Carrier System, which prevents abuse, said Joe A. Douglas, its vice president for government relations. “Payments are adjusted downward as minutes go up. Therefore, there’s no incentive to pump traffic,” he said. But a relatively new category of local phone companies, called “competitive” local carriers,” such as Northern Valley, falls outside of NECA’s purview.

Most Google Voice features handle incoming calls. The service provides a phone number that connects to voice mail or can forward calls to landlines and cellphones. It can also record calls, customize greetings for particular callers and transcribe voice mail. Beginning last week, it could also be an alternative voice-mail destination for a user’s cellphone voice mail.

Small technology companies are also affected by traffic pumping. ZipDX, a telephone conferencing service based in Los Gatos, Calif., charges its customers for its service and must compete against free services in rural areas that are funded by the access fees charged to outside phone companies. David Frankel, the company’s founder, said, “The F.C.C. should say to everyone, ‘If the only purpose of what you’re doing is to rake in access charges, it’s not O.K.’”

A spokesman for the F.C.C. said it had resolved some concerns and “begun an inquiry into what further steps can be taken to prevent both incumbent and competitive carriers from gaming intercarrier compensation rules.”

THE F.C.C. has caught one break: it’s not facing a united front of very large, unhappy complainants. Instead of extending its hand in solidarity to Google as a fellow victim, AT&T went on the attack. In a letter to the F.C.C. last month, it contended that Google was blocking calls not only to sex chat lines, but also to others, like an ambulance service and a Benedictine convent.

Google has responded with improvements in its blocking technology. Instead of blocking by phone number prefix, it blocks only individual numbers, and fewer than 100 nationally are restricted, it reported to the F.C.C. in a filing last week.

It’s only an improvised solution, however, to the problem of traffic pumping, which the F.C.C. should root out. In the meantime, calls to Grandma and to the Benedictine convent now go through; those to highwaymen do not.