American Telephone & Telegraph Co. Chairman Charles Brown, answering skeptics who have suggested the Bell System has lost its interest in telecommunications legislation, yesterday renewed the company's call for action on the controversial issue when the new Congress convenes in January.

"We still believe it is critical that Congress establish firm ground rules for our industry," Brown said in a speech to the annual convention of the U.S. Independent Telephone Association in Chicago.

"Otherwise our future will be decided by commissions acting under outdated statutes or by courts whose function is to decide legal questions, not provide the policy guidance our industry requires."

Brown's call for continuing congressional consideration cames despite some speculation in communications circles that the Bell System's interest in seeking legislation may be fading, particularly in light of Federal Communications Commission action restructuring the industry and allowing the company to participate in unregulated businesses, such as data processing.

The House Judiciary Committee last week effectively killed a major telecommunications bill which had been passed earlier by the House Commerce Committee asserting that the panel did not have adequate time to review the legislation's antitrust consequences.

The committee reported the legislation "adversely" and "without prejudice," leaving the door open for future Judiciary Committee action on the issue.

But despite the progress made on the issue this year -- the farthest the legislation on the subject has gone in Congress since it was brought up four years ago -- Rep. Lionel Van Deerlin (D-Calif.), chairman of the communications subcommittee, suggested last week that reconsideration of the bill next year was anything but certain.

Brown said that although "the legislation currently in Congress does not coincide with what our industry had in mind" when Congress first took up the issue, "this doesn't mean our effort was in vain."

But Brown chided the Judiciary Committee, saying the panel "did almost as much violence to the English language as it did to our hopes for consensus. Will someone tell me how a bill can be reported 'adversely' and 'without prejudice' at the same time?" Brown asked.

Speaking to representatives of smaller telephone concerns, Brown said the industry "should not be reluctant to remind the lawmakers that setting the ground rules for the information age ranks high on the roster of the nation's unfinished business. Regardless of who is elected president, Brown said AT&T hopes telecommunications legislation is given "high priority in 1981."