Ports in Singapore and Seattle this summer will begin carrying out electronic data interchange of ship schedules and container load plans as the first step toward a trans-Pacific EDI network.

Zeger van Asch van Wijck, Seattle port director, said he has concluded a memorandum of understanding with Goon Kok Loon, Singapore's deputy port director, for the two ports to start exchanging ship information by EDI as soon as possible.The Seattle port earlier this year announced plans to pursue development of an international satellite network, or teleport, for movement of EDI messages. Port commissioners in Seattle called for their computer staff to consider developing a system similar to one being used at the Port of New York & New Jersey.

"The EDI link with the Port of Singapore is the Port of Seattle's first step in the development of a teleport," Mr. van Asch van Wijck said.

Cecil Patterson, chief of information systems at the Seattle port, said the two ports are still working out the details, but he expects to be moving data to and from Singapore in standard international messages before the end of the summer.

Preliminary plans call for regular exchange of information on ship

arrivals and departures and on the positioning of each container aboard each ship moving between the two countries, he said.

The two ports are currently evaluating the messages already available under Edifact, a series of EDI formats developed under the auspices of the United Nations. He said the ports may decide to add or delete information from their transfers, depending on what existing Edifact formats can handle.

Seattle plans to work with Singapore on the kind of phone lines or other hookup that will carry the data, Mr. Patterson said. The West Coast port is exploring the idea of using the same carrier Singapore has used for other EDI projects, with Seattle linked to Singapore by way of Hong Kong.

Mr. Patterson said such routing would make it possible for Seattle to expand its system to other Asian ports with feeder connections from several cities to the trunk line between Seattle and Hong Kong.