Timothy Joseph Buzbee took the witness stand today -- speaking publicly for the first time in his own defense--and told a jury in the first of the Aspen Hill rape trials that he did not rape a 15-year-old girl on July 30, 1981.

"Absolutely not," came the emphatic reply when his attorney asked him if he had committed the kidnaping and rape with which he is charged. Buzbee also has been accused of three other rapes, and all four have come to be known as the "Aspen Hill" rapes for the upper-middle-income neighborhood in Montgomery County where they occurred. He has pleaded not guilty to all the charges.

Yesterday afternoon, prosecutor Barry Hamilton, his hands on his hips and his voice rising, took his turn firing a barrage of questions at the defendant.

"Is it not a fact that on the evening of July 30, 1981, you broke into the home of the victim . . . ?" Hamilton asked.

"No sir," said Buzbee.

"Is it not a fact that you forced this 15-year-old child out of her house . . . and into your waiting car?" Hamilton asked, as he moved closer to the witness stand.

"No, sir," came the staccato reply.

"Is it not a fact that you took her to your parents' home . . . and into the bedroom where you raped her . . . ?"

"No, sir," said Buzbee, as the prosecutor finally ended his interrogation in the Montgomery County Circuit Court.

Under questioning by his own attorney, Reginald W. Bours III, Buzbee was unable to state where he had been the night of July 30, 1981.

He acknowledged that Bours had asked him to try to reconstruct the events that evening, but said, "I can't remember anything," of the night more than 21 months ago. Buzbee and other members of his family testified yesterday that Buzbee often worked late at night either at the surveying business he ran for his father or at a series of odd jobs.

As Buzbee began his hour-long testimony, spectators and jurors alike strained forward in their seats to hear him. Buzbee's voice has become a major issue in this case ever since the victim testified that her attacker had a "speech impediment" and that she was able to identify his voice by listening in on a voice line-up conducted by police. Police have testified that the voice she picked out was Buzbee's.

In this, the first of the rape trials, Buzbee is accused of breaking into the victim's home, grabbing her from behind and blindfolding and gagging her before driving her to another house where she was raped. After a lengthy investigation, Buzbee was arrested and charged with the rape last November.

Under questioning by Bours, Buzbee explained why on the night of his arrest, even before the words Aspen Hill were uttered by police, he had called home and told his wife, "Listen honey . . . police have arrested me for the Aspen Hill rapes."

The 25-year-old defendant testified that immediately after his arrest, detectives who told him he was charged with rape also "mentioned they'd been on the cases for 18 months."

Buzbee told the jury that when he asked them why they were taking him to the prosecutor's office, a departure from the usual practice of taking suspects to police headquarters, the detectives said, "because of all the publicity around the case."

Buzbee also testified that when he reached the prosecutor's office and found "20 or 30 people" there after 6 p.m. on a Friday, he asked why, and was told, "They waited around to see what you looked like."

From all that, Buzbee said, "I assumed what I was being arrested for were the Aspen Hill rapes." Those rapes had received extensive publicity in the months before Buzbee's arrest.

Yesterday, under Hamilton's questioning, Buzbee said that he had not asked about specific details, for example, the victim's name or the date of the crime, after he was told he was being charged with rape.

"You weren't at all curious about what you were being arrested for?" the prosecutor inquired. "I didn't say that," Buzbee snapped back, the only departure from the even, calm tone he maintained during the cross-examination.

"You weren't interested in what you were arrested for?" Hamilton prodded.

"Sure I was," said Buzbee.

At one point, Hamilton asked Buzbee if he had ever applied for a job in law enforcement. "Yes, as a cadet in Ocean City," said Buzbee, whose family maintains a summer home there.

"You didn't get the job?" Hamilton asked. The defense objected and the line of questioning stopped before Buzbee could answer.