Image source: magicJack.

Following the release of fourth-quarter results, shares of magicJack VocalTec (CALL) soared as much as 28% higher in after-hours trading.

Analysts were looking for adjusted earnings around $0.41 per share on $36 million in fourth-quarter sales. Instead, magicJack delivered non-GAAP earnings of $0.69 per share and $38 million in total net revenues.

The large earnings surprise includes a $35 million one-time tax benefit, related to various accounting treatment changes in the U.S. and operating losses in Israel.

magicJack CEO Gerald Vento highlighted the strong demand for his company's digital telephony services, as evidenced by growth in magicJack service and app users. "The transformation of magicJack is well under way and we expect our updated branding and expanding distribution channels to pay dividends as the year progresses," he said in a prepared statement.

Looking ahead, magicJack put the midpoint of full-year 2014 revenue guidance at $160 million, comfortably ahead of Street projections at $142 million. Adjusted EBITDA profits should add up to roughly $50 million, again higher than Street estimates at $46 million.

The stock's brief after-hours spike to $22.47 set a new 52-week high. magicJack shares moderated to a more modest 17% extended gain, still exceeding the previous annual high.