Image source: Sonos Networks.

What: Shares of networking equipment provider Sonus Networks (NASDAQ:RBBN) surged as much as 18% higher on Wednesday, lifted by a surprisingly strong earnings report with a side of optimistic forward guidance. by 3:10 p.m., shares were up roughly 11%.

So what: In the second quarter, Sonus' sales fell 28% year-over-year to $54.7 million. These revenues were roughly equally split between product and service sales, compared to a 60/40 split in the year-ago quarter. On an adjusted basis, Sonus reported a net loss of $0.10 per share. That's up from a $0.27 loss per share in the second quarter of 2014.

These results weren't exactly terrific, but analysts expected even worse. Wall Street's consensus view called for a $0.16 loss per share on $54.2 million in overall sales, and Sonus beat both of these targets.

Looking ahead, analysts expect $0.05 of earnings per share in the third quarter and a $0.17 loss per share for the full year. Updated guidance pointed to a $0.07 profit per share in the third quarter and a $0.05 loss for the 2015 fiscal year. Revenue guidance was roughly in line with the current analyst view.

Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

Now what: Today's sudden bounce is not making millionaires, mind you. Sonus shares are still down 64% year-to-date.

A historical perspective can show you some reasons why.

The current batch of relatively optimistic guidance stands far below the 2015 projections offered at the end of 2014. The original tally called for full-year earnings of roughly $0.57 per share on about $328 million in sales. Now we're looking at a $0.05 net loss per share and $247 million in sales.

Specifically, Sonus shares plunged more than 30% in a single day in March, when it reduced those guidance numbers dramatically. Citing expected orders falling through the cracks, the company announced a severe cost-cutting program.

That program is on track to deliver 2015 savings of approximately $20 million, and Sonus also announced new contracts with two unnamed top-tier international telecoms. So the company is both lowering its expenses and landing fresh business, which might signal a return to long-term health.

Might, I said.

Sonus still has a lot to prove here. At the moment, I'm quite content to be a former Sonus shareholder and have no intention of jumping back in this pool anytime soon.