American and Soviet officials held unannounced meetings in Moscow last week on U.S. proposals to improve communications links between the two countries and minimize the likelihood of a nuclear exchange because of a misunderstanding.

The American ideas include improvements to the existing Washington-Moscow hot line and new high-speed links between military command centers and embassies in the two capitals.

The Soviet officials, according to informed U.S. sources, expressed considerable interest in the proposed improvements to the hot line, which currently consists of direct teletype communications between the U.S. and Soviet heads of government for use in emergencies.

But they mostly "just listened" to the details of the other proposals, the sources said. Nevertheless, U.S. specialists say they believe that these talks could be the "skeleton" around which a much better "crisis-control system" can be developed.

The two delegations agreed to meet again but have not set a date, sources here said.

The U.S. contingent was led by the charge d'affaires of the U.S. Embassy in Moscow, Warren Zimmermann, and included officials from the White House, Pentagon and State Department.

The Americans presented three initiatives developed by the Pentagon under legislation sponsored last year by Sens. John W. Warner (R-Va.) and Sam Nunn (D-Ga.) calling for new efforts to control use of nuclear weapons in crisis periods.

The current teletype hot line, housed in the Pentagon with a direct link to the White House, has been used during such crises as the 1967 and 1973 Arab-Israeli wars to prevent Soviet misunderstanding of U.S. fleet movements. But the system, despite some improvements in 1971, is still largely limited to the speed of the teletype operators and translators on both ends.

The U.S. proposal would add a high-speed facsimile capability to the system that would allow transmission of an entire page of material at once, as well as charts, drawings and maps that require no translation but could be useful to either side in understanding a situation.

The second proposal would set up a parallel facsimile link between the two national crisis command centers in the Pentagon and the Kremlin. The third involves installation of high-speed data links between each capital and its embassy in the other capital so that instructions can be handled more quickly.

Defense Secretary Caspar W. Weinberger indicated in a report to Congress last April that the administration favored such "confidence-building" steps.

But no announcement was made of the actual talks on the subject, in part, U.S. officials said, because of the peculiar state of relations between the two superpowers.

On the one hand, U.S.-Soviet contacts have increased in recent months, including meetings between Secretary of State George P. Shultz and Soviet Ambassador to the United States Anatoliy F. Dobrynin.

But there also is an important source of tension dominating the relationship: the deployment of new U.S. cruise and Pershing II medium-range missiles in West Germany, Italy and England slated to begin in December unless an arms pact is reached before then reducing the 600 intermediate-range missiles the Soviets already have in the field.

Moscow bitterly opposes the planned U.S. deployment and still hopes that opposition in western Europe to the controversial U.S. missiles will prevent their installation. Until that theory has been tested, many U.S. specialists believe that Moscow does not want to seem to be making progress with the Reagan administration on security issues.

Yet, officials here say, there are areas where both countries see a mutual interest and where negotiations are continuing quietly. They suggest that the communications talks in Moscow are an example.