Sonus (SONS) slid Tuesday after third-quarter numbers came up short.

The Chelmsford, Mass., voice-over-Internet-protocol gearmaker posted a net loss of $2.7 million, or a penny a share, compared with a 4-cent profit in the previous quarter and a year ago.

Sales of the company's next-generation phone switches in the quarter totaled $45.7 million, compared to $58.1 million in the prior quarter and $46.8 million in the year-ago period.

Analysts were looking for a penny-a-share profit on $48.7 million in revenue in the third quarter, according to a Thomson First Call tally.

Sonus says new accounting guidelines caused the company to defer about $4.7 million in revenue, which translated to a 2-cent deduction from the company's third-quarter bottom line.

Investors didn't cheer the negative surprise.

Sonus emerged from an accounting snag earlier this year after the

Securities and Exchange Commission

cleared the company without penalty after an investigation.

Early last year, Sonus discovered bookkeeping errors dating back to 2001. In the wake of the audit, the company fired several managers for unethical behavior, restated its financial reports from 2001 to 2003 and subsequently fell behind on its filing deadlines and was briefly delisted from the Nasdaq.

"Our global leadership in the VoIP market resulted in the continued solid demand for Sonus' IP voice solutions from network operators around the world," says CEO Hassan Ahmed in a press release Tuesday.

Sonus shares fell 61 cents, or 12%, to $4.45 in postclose trading Tuesday.