RIM (Research In Motion) has added voice capabilities to its BlackBerry handheld device to create the Java-based BlackBerry 5810.

It's demonstrating the new unit at the Comdex Chicago trade show, the company announced on Monday.

Here in Europe mobile phone operator O2, as was BT Wireless, will sell a version of the BlackBerry 5810, though it is not expected to hit the market until the end of the third or fourth quarter, according to O2.

O2 has no plans to demonstrate the BlackBerry 5810 at the CeBit trade show in Hanover, Germany, this month, though it will be showing branded versions of the Handspring Treo and the XDA, O2's version of the Microsoft Pocket PC 2002 Phone Edition.

The BlackBerry PDA (personal digital assistant) is designed to work over GSM/GPRS (global system for mobile communications/general packet radio service) mobile networks with J2ME (Java 2 Platform, Micro Edition) as its core operating system, RIM said in a statement.

Along with voice, the BlackBerry 5810 includes email, a web browser and SMS (short messaging service) capabilities as well as organiser functions such as a calendar and address book that are used with a miniature keyboard.

The BlackBerry 5810 joins other combination mobile phone and PDA products on or coming to the market, such as the Handspring Treo, which is expected to hit shelves next month and the Nokia 9210 Communicator smartphone from Nokia, which is based on the Symbian operating system and began selling in Europe last year.

Also coming is the HP Jornada 928 Wireless Digital Assistant, the first branded Microsoft Pocket PC 2002 Phone Edition device.

The BlackBerry device is aimed, initially, at business customers. Versions of the BlackBerry without voice capabilities are currently being used by about 6,500 companies, said RIM UK spokeswoman Tilly Quanjer.

"The BlackBerry 5810 is different from, say, the Treo because it is an end-to-end solution for enterprises and comes with end-to-end security. Plus it has push technology, which means that BlackBerry sends your email to you, so it just arrives, whereas with the Treo you have to download it," Quanjer said.