Sony to Unveil Personal Communicator: Analysts say the device to be introduced today provides the first real glimpse of the lofty promises of the first hand-held communications gadgets. Using a much-awaited service developed by AT&T; Co. called PersonaLink, the device acts as a telephone and can also send and receive faxes, electronic mail and pages. The system has an intelligent agent, an electronic "slave" that has the potential to ferret out information and perform tasks requested by the user. Sony Corp.'s paperback-size device, called Magic Link, is the latest entry into the market for personal digital assistants. Sony said Magic Link will sell for a suggested retail price of $995. Extra options include a phone headset, portable computer keyboard and a pager card.