CHARLOTTE–US LEC Corp. (Nasdaq:CLEC), a super-regional telecommunications carrier based in Charlotte, says its base of business customer surpassed 18,000 in the first quarter.

Approaching release of its first quarter SEC filing, the company said it had strong first quarter sales and saw its 5th consecutive increase in revenue.

The company introduced two new data products in 2004, managed router services and a voice over Internet Protocol (VoIP) product.

The company’s quarterly earnings call is set for April 27.