Vincent P. Biunno, the U.S. District Court judge who seems to have delayed the antitrust settlement between the federal government and American Telephone & Telegraph Co., has a reputation for taking his time in making decisions and for shunning controversy.

But last Monday, the 65-year-old Biunno madewhat appeared to be a snap decision[Illegible Word] at least temporary[Illegible Word] the best-laid plans ofjustice department attorneys and ATT.

Biunno,[Illegible Word] District Court hasjust won over a 1956 consent onwhich the settlement is based, was[Illegible word] by federal andtelephone company lawyers to transferjurisdiction to the U.S. court in Washington where the seven-year-old case against AT&T was being tried. The Justice Department and AT&T felt that the trial judge, Harold H. Greene, would be best to sign the modified consent decree and hold public hearings on it.

Instead, Biunno signed the modification to the consent decree -- the centerpiece of the settlement -- and held off ruling on the transfer. Greene called the case "too important" to be settled on such a "haphazard basis."

"I have to laugh," said a former colleague. "He's a complex man and I am not surprised that he did it [signed the modified consent decree rather than transfering it to Washington]. But for a man who avoided controversy, he's sure got it."

Biunno, appointed to the federal bench in 1973 by former President Nixon, has not been available for public comment since he signed the consent modification. Calls to his Newark chambers went unanswered.

His friends say that Biunno is a top legal scholar and that during the more than 30 years that he was in private practice he did little trial work. "Vince liked the complex technical stuff that drove the rest of us nuts," said a former colleague. However, the colleague said, Biunno would concentrate mainly on the issues that interested him and let the others wither. "I doubt he cared much for criminal trials or most civil trials."

But regulation of the telephone company was one of those issues that interested him.He was New Jersey's state counsel for telephone and other utility rate cases until he was appointed as judge.

Even his critics in the New Jersey bar, who are numerous, describe Biunno with words such as "brilliant," "scholarly" and "humane." But they say Biunno has had his share of reversals by appellate courts and say he has a tendency to go off on didactic tangents.

"He gets something into his head and you can't change it," said one attorney who has argued numerous cases before the judge.

Another attorney cited a 1979 case to illustrate his problems with appeals courts. In that case Biunno issued a preliminary injunction blocking the National Association of Securities Dealers from halting a brokerage firm's alleged fraudulent sales and market manipulation.

The Third Circuit Court of Appeals overturned his decision using extremely harsh language.

Friends and critics said that Biunno, who is in ill health and has applied for retirement, long has fancied himself an expert on complex industries like the telephone industry. "He often goes out of his way to demonstrate that knowledge," said an attorney who has tried cases before him.

Even in the brief hearing held last Monday, Biunno discussed at length the implications of the proposed settlement, under which AT&T will spin off its 22 local operating subsidiaries, for the regulatory process.

"I'm quite familiar with it," Biunno said. "I represented customers for three years in all rate proceedings... I have been through this process. I'm familiar with the structure of existing charges in this particular kind of utility, not only the Bell System, but independents as well. There are some independents in New Jersey, in case you didn't know."

Biunno has had a long fascination with telecommunications, science and computers. For 15 years, until he joined the bench, he was a member of the American Bar Association's committee on electronic data retrieval. One colleague recounted that Biunno, in one telephone company hearing, bought nearly all types of telephones and then proceeded to question telephone company officials about the construction of each of them. "He'd ask why there were two buttons on this phone and three on another," the colleague said.

Neither friends nor critics say they know why Biunno chose to sign the modified consent decree rather than transfer that authority to Washington.