Nortel announced a variety of mixed news Thursday in its quarterly earnings report.

The telecommunications equipment manufacturer (NYSE: NT) said it posted a profit of $179 million on sales of $7.27 billion in the quarter. Sales in wireless equipment triggered Nortel’s return to black, although revenues were down $6 million from the previous quarter.

Nortel stock closed at $4.44 a share on Thursday. It was selling at $4.31 in London early today.

However, Nortel also said it was going to review reports for 2000 through 2002, conceded that the staggering losses it reported may have been overstated. Nortel reported $31 billion in losses as the telecom sector imploded. The company laid off two thirds of its staff — more than 60,000 workers — and also reduced the number of facilities it operates to 250 from 700.

Now, Nortel says losses may have been overstated by as much as $900 million.

Frank Dunn, Nortel’s current chief executive officer, was the chief financial officer at the time of those reports.

“The challenges that faced Nortel Networks and our industry over the past few years were unprecedented,” Dun said in a statement. “It is clear now that in such a volatile environment, errors were made.”

Nortel recently announced plans to build a new research and development center in China and to hire additional workers there.