First there was the EO Personal Communicator from AT&T;, which was deemed so expensive and hard to use that it is no longer made.

Then came the Newton Message Pad from Apple, whose initial handwriting recognition software became the butt of jokes, and which has had total sales of only about 100,000 units after more than a year on the market.

Now, hoping for better results, the consumer-electronics giant Sony Electronics is introducing the latest attempt at a portable computer-communications device – with, as it turns out, the help of AT&T; Corp. and Apple Computer. Not to mention Motorola, another partner in this multi-corporate effort, in which Matsushita Electric Industrial Co. of Japan and Philips Electronics N.V. of the Netherlands also have roles.

The $995 product, called the Magic Link PIC 1000, went on sale Wednesday at more than 1,000 consumer electronics stores around the United States, such as Circuit City and others that already sell computers and Sony products.

The PIC- which stands for Personal Intelligent Communicator – is about the size of a fat paperback book. It represents the most ambitious attempt yet by computer and communications companies to pool their resources in hopes of finally creating a market for what the industry calls “personal digital assistants.”

With the Magic Link, an executive on the go is supposed to be able to send and receive electronic mail, make airline reservations, check stock quotes and conduct other personal business – without having to learn complicated computer commands.

The product also has been designed as the first application for a new nationwide AT&T; network, PersonaLink, which makes use of “intelligent agent” software that enables a message to find the recipient even if the sender has no address.

These agents also can do their master’s bidding in other ways, such as being able to carry out the command “Page me, if I receive mail from the boss.”