Updated from 12:36 p.m. EDT

Technology stocks moved modestly higher Thursday, despite a number of the biggest movers heading in the opposite direction on poor earnings news.

In the broader technology sector, the Nasdaq 100 traded up 15.4 points to about 1813.5.

Software maker ECtel ( ECTX), however, plunged 28.9% after it warned that first-quarter revenue would be well below expectations. The company sees revenue of $3.4 million to $3.6 million.

"Our first quarter revenues were lower than our internal work plan following both a delay in the receipt of previously anticipated orders and a delay in receiving acceptance for certain customer projects that are part of our backlog," the company said, adding that the shortfall is also expected to impact earnings. Analysts project earnings of 3 cents a share on revenue of $7.5 million. Shares closed down $1.31 to $3.23.

Shares of Interphase ( INPH) also were hammered after the maker of telecom equipment warned first-quarter results would be lower than expected. The company sees a loss of $1.7 million to $2.2 million on revenue of $5 million to $5.1 million. Analysts project earnings of a penny a share on revenue of $8.35 million. Shares closed down $3.32, or 24%, to $10.34.

Research In Motion ( RIMM) slid 8.2% after the BlackBerry maker posted disappointing fourth-quarter results and said it is being formally investigated by the Securities and Exchange Commission. The company earned $187.9 million, or 99 cents a share, on revenue of $930.4 million. Analysts expected earnings of $1 a share on revenue of $935.4 million.

The company also said the SEC is formally investigating its historical stock option practices. Previously, the SEC was only looking at the company on an informal basis. "The company believes that the focus of this investigation is substantially the same as the informal inquiry," Research In Motion said. Shares closed down $11.92 to $134.10.

Mobius Management Systems ( MOBI), meanwhile, vaulted after the company agreed to be acquired by Allen Systems Group for about $200 million, or $10.05 a share. The all-cash deal represents a 35% premium over the company's closing price of $7.44 on Wednesday. The deal is expected to close during the third quarter.

Mobius, however, also cut its third-quarter earnings and revenue guidance. The company now sees a loss of 8 cents to 10 cents a share on revenue of $18.7 million to $19.2 million. Previously, the company forecast a profit of a penny a share to a loss of 2 cents a share on revenue of $22 million to $23 million. Analysts polled by Thomson First Call project break-even earnings on revenue of $22.2 million. Shares were trading up $2.35, or 31.6%, to $9.79.

Shares of beleaguered Vonage ( VG) also headed higher, as the Internet phone company announced the immediate resignation of its chief executive officer. Michael Snyder will be replaced by Jeffrey Citron, the company's chairman, on an interim basis until a full-time replacement is found.

Meanwhile, the company said that it expects to post first-quarter revenue of $195 million. Analysts project revenue of $197 million. Vonage also announced plans to cut annual expenses by about $140 million. The bulk of the reduction will occur in marketing expenses, but the company also plans to reduce expenses through consolidation of operations and job cuts. Shares were trading up 20 cents, or 6.7%, to $3.20.

Other technology movers included Intel ( INTC), up 3 cents to $20.50; Microsoft ( MSFT), up 43 cents to $28.54; Applied Materials ( AMAT), up 12 cents to $19.35; Sun Microsystems ( SUNW), which was up 1 cent earlier in the day but closed flat at $5.90; Cisco Systems ( CSCO), up 18 cents to $25.97; and Apple ( AAPL), down 40 cents to $92.19.