RadioShack Corp's quarterly profit missed estimates by one cent on weak demand for its converter boxes, laptop computers and wireless accessories.

The electronics retailer said on Monday its net income fell to $37.4 million, or 30 cents a share in the third quarter, from $49.1 million, or 38 cents a share, a year earlier.

Analysts on average were expecting a profit of 31 cents a share, according to Thomson Reuters I/B/E/S.

Total net sales fell 3.1 percent to $990 million.

Sales at its stores and kiosks open at least a year fell 2.9 percent.

RadioShack had seen an uptick in sales of its converter boxes due to a mandatory switch of all U.S. televisions to digital in June this year. In July, it forecast a decline in the sales of these units in the rest of the year.

The retailer faces a challenging sales environment as consumers tighten their purse strings and curb their appetite for non-essential items in the recession.

It also has to fight fierce competition from national big-box retailers like Best Buy , discounters like Wal-Mart as well as wireless carriers and other new wireless distribution channels.

Earlier this month, Wal-Mart said it will sell discounted mobile services nationwide, threatening to aggravate a price war and hurt profit margins across the U.S. wireless sector.

RadioShack strengthened its merchandise mix by adding popular products such as iPods and iPod accessories. It also signed a deal with T-Mobile USA Inc to expand its wireless offerings.

(Reporting by Dhanya Skariachan; Editing by Derek Caney)