The Federal Communications Commission yesterday again reaffirmed, at least for the time being, the right of consumers to buy and install their own telephones, without securing any equipment from the Bell System or local telephone companies.

In a unanimous vote, the FCC rejected a request from American Telephone & Telegraph Co. and other phone companies for a partial halt to the agency's program permitting the connection of customer-provided phones to the national network, pending consideration of a new idea the industry recently proposed.

Under current FCC policy, consumers now are allowed to connect their own terminal equipment - main and extension telephones as well as other kinds of phone systems - to the network without carrier-supplied protective devices. The equipments, however, must comply with standards incorporated into an FCC registration program to protect the nation's telephone network from harm. The program took effect last month after the Supreme Court declined to review an appeals court ruling.

The industry recently proposed a revision to the program, which the commission said it would consider soon. The change would require most residential telephone customers, those with single-line service, to use at least one telephone supplied by the phone company.

The telephone companies contend that the provision of the "primary instrument" would allow them to locate service problems more easily than if customers depend solely on equipment from other manufacturers.

Pending the commission's consideration of this idea, the phone companies also sought a stay of the program to prevent telephone users from replacing their Bell-provided main telephone with equipment now available from independent suppliers.

The seven commissioners including Tyrone Brown, the newest member accepted the recommendations of their top staff to deny the stay. Walter R. Hinchman, chief of the FCC's Common Carrier Bureau, said the burden of proof lies with the industry when it seeks to alter a policy already found to be in the public interest by the commission. He said the industry had not submitted evidence showing that the program would result in irreparable harm to the system.

In response to the FCC decision, an AT&T spokesman said the company regretted that the commission "didn't see fit to grant the stay we believed was necessary" to protect telephone customers but it would "put its best foot forward" when filing documents and evidence requested by the agency for its study of the primary instrument concept.

A spokesman for the U.S. Independent Telephone Association said it considered the FCC's action "not to be in the best interests of the nation's telephone users" and that there would have been "less confusion to consumers" if the partial stay had been granted.