Educational software maker Blackboard Inc. said Monday that it will spend $33 million in cash to acquire privately held Saf-T-Net Inc., which produces an alert system for child safety.

Saf-T-Net's system sends out emergency messages for parents and others caring for children via phone calls, e-mail and text messages.

The acquisition broadens Blackboard's ability to provide customers with mass notification, said CEO Michael Chasen.

Blackboard expects the deal to close in late March, so it won't affect first-quarter results. However, it expects it to add $5.5 million to 2010 revenue and reduce earnings by 9 cents per share, or 5 cents per share excluding one-time charges.

Blackboard now expects revenue of $429.5 million to $445.5 million for this year, and earnings of 56 cents to 85 cents per share.

The new system will begin to add to earnings beginning next year, Blackboard said.

Saf-T-Net is based in Raleigh, N.C., and has a staff of 65. It has more than 2,000 K-12 clients, Blackboard said.

Shares of Blackboard, based in Washington, D.C., rose one cent to $42.56 Monday.