AT&T and network equipment maker Cisco Systems Inc will start selling a high-tech video conferencing system together later this year aiming at boosting their sales to multinational corporate clients.

Sales for Cisco's video conferencing system called TelPresence have been increasing gradually but limited only to a few top global companies.

Cisco's TePresence, which was introduced in 2006, has high-definition screens and easy-to-use dial-in features.

The partnership between AT&T and Cisco will increase the two firm's sales force and also enable video conferencing among multiple corporate customers compared to the current situation, which involves only intra-company use only.

The two companies said they will start selling the joint service in the second half of 2008 in 23 countries and expand to more countries in 2009.

In a statement released on Monday, both firms confirmed that the service will be sold as a corporate telecommunications service including remote help and on-site equipment maintenance rather than a one-off equipment sale.

The TelePresence 3000, sold in the form of a small conference room with three high-definition screens was originally sold at $299,000 per unit, and another cheaper one-screen option will also be available through AT&T-Cisco partnership, said the two companies in a joint statement.

Other competitors in the corporate video conferencing business include Hewlett-Packard, Verizon Business, a unit of Verizon Communications Inc., and Polycomm Inc.