Research In Motion will release its own tablet PC in the fourth quarter together with a new operating system that will run it, according to sources familiar with the BlackBerry maker's plans.

The RIM tablet PC dubbed BlackPad is to be announced at the developers' conference in San Francisco next week, the sources said.

The BlackPad features a 7-inch touch screen and one or two built-in cameras. It has a Bluetooth and can connect to the Internet via mobile phone networks using a BlackBerry smartphone.

Instead of the BlackBerry 6 operating system, the BlackPad will run in an OS built by QNX Software Systems and chips made by Marvell Technology Group.

RIM bought QNX early this year. Its new operating system will replace the BlackBerry 6 OS

Taiwan's Quanta Computer Inc. is reportedly the manufacturer of the BlackPad, the sources further said.

RIM, Quanta and Marvell all declined to confirm the report.