U.S. Postal Service executives have taken the first significant step to inaugurate the era of electronic mail delivery that is expected in the 1980s.

Postmaster General William F. Bolger revealed yesterday that he has approved a $4 million laboratory experiment in Rockville starting next year to test prototype Postal Service equipment that will print at high speeds message received by satellite communication.

If the test is successful - and Bolger said the "chances are" that it will be - the Postal Service will move to conduct a full field test of the electronic system in up to 10 cities across the nation. It would take about three years to construct the proposed fieldtest network, Bolger added.

Thereafter, the Postal Service would expand the service to a total of 87 cities - a system that would cost some $2 billion to put in place. But Bolger and other senior postal authorities said, cities would be added in increments, with revenues financing most of the expansion and Postal Service commitments never exceeding $200 million at any on time.

Bolger detailed his decision at a meeting with reporters late yesterday and also called on Congress and the White house to make a fundamental policy decision about whether the Postal Service ultimately should enter the electronic message business in such a big way.

The postmaster general already has briefed congressional, White house and Federal Communications Commission aides on the Postal Service decision, which followed recommendations made by RCA Corp. at the conclusion of a two-year study of the feasibility of electronic delivery.

Postal Service plans are expected to become a hot potato for members of Congress and federal regulators because American Telephone & Telegraph Co. and other corporate giants plan to offer all sorts of intercity electronic mail, electronic data, information retrieval and money transfers services through new telecommunications technology.

The technology, bouncing messages off satellites, has existed for some time. And RCA Corp., in its $2.3 million study, recommended several approaches as feasible for the Postal Service.

Bolger has decided to act on RCA's proposal for electronic mail messages. Messages would be delivered to specified post offices or sent by computer link for large-volume users. At the sion. At receiving stations, the data would be coverted into language and printed out 10 sheets a second and seal the messages in envelopes for delivery the following day.

With adequate volume, the cost per electronic message could be about 10 or 11 cents compared with the current 15-cent first-class stamp. Bolger said the RCA study predicted that about 25 billion pieces of mail a year may be candidates for electronic delivery; postal voulume in the year ended Sept. 30 was 96 billion pieces, and that is expected to rise to 100 billion in 1980. From D7>

Bolger also noted that a new business-oriented Electroni Computer-Originated Mail (ECOM) service will start "hopefully within the next 45 days." This service is similar to Mailgram but aimed at the 750 largest corporations with computer capacity and billing volume to make it a viable alternative to regular mails.

ECOM, which still requires Postal Rate Commission approval, could handle some 15 billion pieces of mail by the mid-1980s.

Bolger said introduction of electronic mail would mean a "considerable drop in the number of people needed to distribute the mails."

He emphasized that a "public policy decision must be made . . . I do not think we should take huge sums and invest until [the policy] is addressed." He added that the "best estimate" is that "hard copy is going to be there" in future years despite forecasts that telephone-television connections and home printouts might reduce postal volume.

Bolger said postal officials' primary goals are increasing volume and keeping general rates steady to prevent erosion of business as new technology takes hold and leads to improved future delivery.