Cable & Wireless Plc is expanding in the airline and travel reservation systems market in Hong Kong: its Cable & Wireless (HK) Ltd unit has formed a joint venture with Cathay Pacific Airways to market the Abacus travel reservation system to agents: Abacus, owned by Cathay with the national airlines of Malaysia, Singapore, Taiwan and the Philippines, replaces the existing Cathay reservation system and a separate booking system owned by Cable & Wireless, and will link to the US PARS system of Northwest Orient and Trans World Airlines, and the European Amadeus system.