The Federal Communications Commission is set to vote unanimously for a record-setting fine against CBS-owned stations for violating broadcast decency standards with the network's January breast-baring Super Bowl halftime show, though some commissioners are expected to say the fines are not severe enough, FCC sources said.

The $550,000 indecency fine would be the largest levied against a television broadcaster. The decision could be released as early as next week but may come the week after, said the sources, who would not speak for attribution because the vote has not been made public. The amount represents a $27,500 fine directed at each of the 20 television stations owned by CBS, which in turn is owned by Viacom Inc.

Excluded from the fines are CBS's more than 200 affiliate stations, which also broadcast the show. That exclusion is one source of disagreement among the five members of the FCC, according to the sources, who are familiar with the commission's deliberations.

A spokesman for the FCC would not comment on the pending ruling.

"We would be extremely disappointed," CBS said in a statement issued last night. "While we regret that the incident occurred, and have apologized to our viewers, we continue to believe that nothing in the Super Bowl broadcast violated indecency laws.

"We would obviously review all of our options to respond to the ruling and we continue to call on the FCC to address serious issues raised by the more than 30 industry participants who challenged the FCC's sweeping new indecency policy," the statement said.

When the vote is released, it will be accompanied by statements from the commissioners, some of whom are expected to take exception to portions of the ruling.

In his statement, Commissioner Jonathan S. Adelstein is expected to argue that the FCC received complaints about the broadcast from viewers watching on all CBS affiliates -- more than 90 million saw the primetime broadcast -- and that the affiliates should be fined as well, sources said.

Further, the FCC's enforcement bureau ruled that only Janet Jackson's brief exposure, which occurred when singer Justin Timberlake ripped off part of her leather bodice, was indecent. The agency also received complaints about the entire show, produced by Viacom-owned MTV, which featured a crotch-grabbing rapper and several S&M-clad dancers gyrating behind Jackson and Timberlake.

Some commissioners are expected to argue that other incidents within the halftime show should have been ruled indecent and subject to fines as well.

CBS has said that it investigated the incident and found that no one at CBS, MTV or Viacom knew what Timberlake planned to do. The network also has apologized.

In July, the FCC's enforcement bureau judged that Jackson's brief exposure violated the agency's decency rules, which prohibit networks from broadcasting sexual or scatological content between 6 a.m. and 10 p.m., when children are most likely to be watching.

The maximum allowable fine for violating the standards is $27,500. However, bills pending in each house of Congress would allow the FCC to fine broadcasters up to $500,000. Further, the FCC has begun levying fines for each instance of indecency within a broadcast, rather than one fine per broadcast.

FCC Chairman Michael K. Powell took the unusual step of personally launching an indecency investigation on the day after the Super Bowl. The FCC's enforcement bureau took up the case and concluded the investigation faster than usual.

The enforcement bureau said it did not fine the CBS affiliates because they had no control over the production of the halftime show and no knowledge it would contain racy material.

The Super Bowl incident was the best known of a number of offensive radio and television broadcasts during the past two years that have spurred outrage from viewers and action from lawmakers.

Radio giant Clear Channel Communications Inc. paid $1.75 million to erase all pending FCC indecency charges, including some against Howard Stern, whose show was pulled from Clear Channel stations in February. Last month, radio and television broadcaster Emmis Communications Corp. paid $300,000 to settle similar charges.

The enforcement bureau is expected to rule soon on a December 2003 Fox awards program during which actress Nicole Richie used two expletives. In March, the agency ruled that an on-air profanity uttered on NBC by U2 frontman Bono was both indecent and profane, though it did not fine the network. In April, a group of radio and television broadcasters and performers urged the FCC to reverse that ruling, fearing a chilling effect on free speech.

Justin Timberlake prepares to tear off part of Janet Jackson's costume at their Super Bowl halftime show. FCC Chairman Michael K. Powell started an investigation the day after the Super Bowl.