Motorola plans to acquire wireless mobile device developer Symbol Technologies for $3.9 billion, the companies have announced.

Symbol makes a range of devices for businesses, including handheld computers that may include bar code scanners, RFID technologies and Wi-Fi. They are widely used by workers in warehouses and large retail outlets, and by delivery services.

The acquisition would fit with Motorola's history as a developer of mobile phones and two-way radios, and advances its push into companies' mobile computing strategies, it said. Motorola has traditionally catered to businesses, notably with is push-to-talk technology used by Nextel in the U.S., and with its Canopy broadband wireless infrastructure business.

While Symbol’s products have a broad customer base the company has faced hurdles in the past few years. In 2004, the U.S. Securities and Exchange Commission fined Symbol $37 million fine for fraudulent accounting practices. Eleven executives were charged with securities fraud including the former chief executive, who subsequently fled the U.S.

Rumours had surfaced over the past few days that Symbol was looking for a buyer.

The deal is expected to close later this year or early in 2007, subject to regulatory and other approvals. Symbol will become a Motorola subsidiary and continue to operate from its headquarters in Holtsville, N.Y.