3Com Corp. said it expects its fiscal second-quarter results and revenue to be lower than forecast because of delayed sales to telecommunications companies. The announcement sent its shares tumbling as much as 27% in after-hours trading. Santa Clara, Calif.-based 3Com said it expects a loss of between 19 and 23 cents a share for the quarter ended Friday, wider than the 7 to 9 cents a share previously forecast. The company expects sales in the range of $765 million to $780 million. It had earlier forecast sales of $870 million to $910 million. 3Com said restructuring by some of its largest customers, consolidation and financing constraints among smaller customers hurt sales. 3Com shares rose 44 cents to close at $13.38 on Nasdaq, but fell as low as $9.75 in after-hours trading.