Flags waved, church bells pealed, congregations united in prayer and white armbands began to appear as Americans united in support of the U.S. hostages held in Iran.

President Carter, in 7,500 letters and Mailgrams, Wednesday appealed to Americans to express their sentiments about the Iran crisis by ringing church bells at noon daily and by writing to Iran's mission to the United Nations.

Cardinal John Cody of Chicago asked Roman Catholic churches in Cook and Lake counties to comply, and urged congregations to pray for the hostages.

The bells of the Travis Park Methodist Church in San Antonio, Tex., will ring 50 times daily until the 50 hostages are released, said the Rev. Dan E. Solomon.

"The whole world is being held hostage right now by the events in Iran," he said.

An anonymous woman caller to radio station WSOC talk-show host Dick Pomerantz in Charlotte, N.C., suggested that white armbands would be an appropriate symbol of support for the hostages.

Sen. Robert Morgan (D-N.C.) extolled the idea on the Senate floor, and radio stations in California, Michigan, Massachusetts, Georgia and New York took up the plan. Some businesses in North Carolina were offering the armbands free.

"The idea seems to be spreading across the country," said Morgan. "Wearing an armband won't free the hostages or have any effect on an irrational dictator or fanatical students, but it says a great deal about the way our country is united in this crisis."

"It's just an apolitical way that we can remember those people," said Ronn Owens of San Francisco radio station KGO.

In other developments:

Evansville, Ind., police said they were protesting the crisis by cracking down on speeders to diminish the need for foreign oil.

The Pennsylvania Senate condemned the embassy takeover, saying that the Ayatollah Ruhollah Khomeini and his followers are "terrorists, outlaws." t

California state Sen. John Briggs filed suit on behalf of state taxpayers to stop aid payments to alien, non-immigrant Iranian students at public elementary and secondary schools, community colleges and state universities.

About 200 people, chanting "deport the shah, not the students," rallied in Seattle at the University of Washington in a noisy demonstration against U.S. policies in Iran. There was some heckling, but no violence or injuries were reported.

A pro-Iranian rally in Albany, N.Y., called by the Socialist Workers Party, was interrupted for more than an hour Wednesday night by more than 100 Albany State University students demonstrating against Iran.

About 70 people showed up at the Holiday Inn in Spokane, Wash., to hear George Bible explore the possibility of a private expeditionary force to free the U.S. hostages being held in Iran.

The soft-spoken local businessman criticized the Carter administration for failing to act effectively to win their release. There were mixed emotions among the audience, and there was also some doubt as to whether any action would be taken.

Bible said he represents a "group of concerned Americans around the country, most of them veterans of Vietnam, who are concerned about the well-being of Americans being held hostage in Iran."