AM International Inc. -- a Los Angeles firm better known by its former name, Addressograph-Multigraph -- was selected yesterday by a Washington satellite communications company to provide high-speed, computerized copier technology for a planned national network.

The AM International Communications system could function as electronic mail delivery by using facilities that can send exact copies of up to 3,600 pages an hour to a distant location.

Satellite Business Systems (SBS), based in McLean, picked AM International after asking more than 60 companies around the world to provide information on a proposed satellite transmission service for documents.

SBS is owned by subsidiaries of Aetna Life & Casualty Co., International Business Machines Corp, and Communications Satellite Corp. It plans to launch two satellites late in 1980 and begin commercial service the following year.

The proposed SBS network would provide for intracompany business communications, government agencies and other organizations with large-volume communications requirements and dispersed facilities.

However, the U.S. Postal Service also has proposed its own national electronic mail network, and government policymakers are wrestling with the potential competition for such services, whether the post offices should be involved and what should be the role of telephone giant American Telephone & Telegraph in the country's future telecommunications system.

AM International, whose chairman is former Nixon administration budget director Roy Ash, has developed high-speed document communications terminals and will deliver prototypes to SBS for demonstrations.

In the announcement yesterday, AM International said its system will be 120 times faster than the most common facsimile devices of today and will "upgrade image quality to compare favorably with original typewritten information."

SBS said customers in the future may replace conventional internal mail systems and messaging equipment with the high-speed copiers.

"Letters, business correspondence, charts, graphs and all forms of written and printed communications will be transmitted from one point to another in seconds instead of having to be hand-delivered over a period of days," said Ash.

In addition to the copier facilities, SBS is planning to offer computer-tocomputer data communications and video conference equipment.