The phone rang at 8:30 at the Eighth Avenue headquarters of Amnesty International USA, bringing word of a disappearance from a small village in El Salvador. Staffer Sarah Krakauer took down the information and telexed it to Amnesty International in London, where 70 researchers spend their days compiling evidence of repression, imprisonment, torture and execution around the globe. And so, a week before today's 25th anniversary of the organization's founding, an ordinary Amnesty day began.

At the weekly staff meeting, an hour or so later, Executive Director Jack Healey reported on his latest session on South Africa with Assistant Secretary of State Chester Crocker; on AI's testimony before a House subcommittee on the suppression of political dissent in Taiwan; on a forthcoming report on torture in South Korea.

Afterward, returning to their cramped office with the yellow "SOS East Timor" buttons stabbed into a bulletin board, Michael O'Reilly and Peter Larson considered which AI group should handle the case of an arrested Sri Lankan. One of the separatist Tamil minority, the man -- age, occupation, health and family circumstances all unknown -- was being detained without charges or a trial date. Groups in Boston, Memphis, Kingston, R.I., and Chico, Calif., were waiting to "adopt" a prisoner -- to write government officials and wardens, politely, insistently, for months, sometimes years, on his behalf.

Down the hall Krakauer, who coordinates the small relief program for the families of the prisoners AI adopts, thumbed through a file of requests growing on her desk. Group 19 from Palo Alto, Calif., which has been letter-writing for a Zaire man arrested presumably for involvement in the political opposition, wanted $200 to help pay his lawyer. The man has been imprisoned for two years now without being charged or tried. Group 113 in Chicago wanted $100 to help support the wife of its adopted prisoner, a Chilean construction worker who disappeared late in 1976.

The map on Membership Director Susannah Sirkin's office wall shows that Amnesty International USA has 307 prisoner adoption groups (red pins) plus 200 campus groups (blue pins) across this country. Worldwide, the Nobel Prize-winning human rights organization has more than half a million members in about 100 countries. There are bound to be proclamations and toasts among them this day, celebrating AI's founding by a British lawyer in 1961. In the United States, AI is gearing up for six benefit concerts next month -- Sting and U2 headlining, Bill Graham producing -- that will help raise money, membership and consciousness.

But staffers here plan no anniversary party; indeed, they dislike the word "celebration," finding "observance" more appropriate. "We've got as many problems as we've ever had," Sirkin said quietly. "We're more capable of documenting more abuses around the world. We're not going to sit back feeling good about ourselves on the 28th."

To work for AI is to constantly weigh the victories -- of the 5,000 names on the organization's list of adopted or investigated prisoners each year, about 1,000 go free -- against the daunting amount of governmental inhumanity constantly being catalogued. It is depressingly simple to find 1,000 new prisoners each year being detained without trial; jailed for what they write, think or say; or abused in prison.

In an interview last week, Healey pointed to several accomplishments. Perhaps most critical was the organization's sense that it had at last earned a permanent place on the international agenda for its concerns. "For 20 years it was pretty lonely," Healey recalled. "Now there can't be a significant international forum without talk about human rights . . . It must be dealt with."

Even the Reagan administration, in whose councils AI initially felt less than welcome, is willing to praise its work. Assistant Secretary of State for Human Rights Richard Schifter, for instance, thinks that AI is more willing to condemn human rights abuses by some governments than by others ("Since there are more human rights violations in Soviet-sphere countries than in western democracies, there is some failure to assess things proportionately"). But overall, Schifter says, the organization has "brought about tangible improvements" in preventing torture and protecting political prisoners.

AI groups may write for months or years without response, notes Schifter's Carter administration counterpart, Patricia Derian, but there is evidence that their message gets through nevertheless. "I had occasion to go to the countries [AI groups] complained about," Derian recalls. "Usually, before I could raise the issue, some high official of the government asked me if I could get Amnesty International to stop writing."

Healey treasures certain favorite war stories, like the time AI, despairing of interesting the national media in mass detentions in East Timor, rented half a dozen billboards around Washington, "so all the aides driving to work could see them. The Indonesian government went crazy." When Ferdinand Marcos visited the United States in 1982, AI staffers made sure that virtually every journalist and government official scheduled to meet with him got copies of the AI report on human rights violations in the Philippines. "Everyone asked him about it," Healey grinned. "Then he got to San Francisco, got off the plane, and Mayor Feinstein handed him the report at the foot of the runway . . . We have to be at least as hard-working -- and smarter -- than the guys doing the nasty stuff."

As for the criticism from various quarters that it is soft on one or another regime, or ought to be, the organization is largely inured to it after 25 years. "We're used to government excuses," Healey said, shrugging. "One is, 'Things are getting better.' That could mean that you've killed off most of the troublemakers . . . Or, 'It's the opposition groups.' In El Salvador we heard that for years . . . One I like is the Russians sending someone to jail for a 'neurotic interest in justice.'

"Our job is to report any government with a human rights violation. We don't give a damn who it is or who it's aligned with."

Yet Healey acknowledged the frustrations and depression inherent in the work AI does. The reports from London sometimes bring horrifying allegations about the ingenuity jailers use to find new means of torture: the application of heated skewers in Syria, suspended burning tires dripping molten rubber onto the bodies of prisoners in Uganda.

"It's gruesome; you just cringe," he said. "You know you haven't done enough. When's enough enough?"

Last week, for example, Charles Fulwood, organizing the Campaign Against the Death Penalty that AI will mount this fall, found a newspaper clipping about a prisoner's electrocution in Florida waiting on his desk when he came to work. He added Ronald Straight's name to the list he keeps on his bulletin board -- the 40th U.S. execution since Fulwood joined the staff two years ago, the eighth this year. "There are depressing things that float through this office," he said. Amnesty International is braced for flak when it begins its campaign against capital punishment in the United States, which has more than 1,700 prisoners on its various death rows. AI's own polls show that the majority of Americans think some crimes deserve capital punishment.

To try to prevent paralysis because of all the things its members and staff have failed to do, AI often segments its campaigns into more manageable goals. It has not succeeded in stopping the governments of the world from detaining citizens without charge or trial, but it has helped to lower the legally permissible period of incommunicado detention in Turkish jails from 45 days to from 15 to 30. It probably will not persuade the 37 U.S. states with death penalties to abolish them, but it may prod legislatures to hold hearings, may mobilize public opinion, may succeed in one state -- Nebraska -- deemed ripe for lobbying for abolition.

Not surprisingly, there's a lot of gallows humor around the AI offices. One bulletin board displays a cartoon "AI Man," a dumpy caped crusader armed with a fountain pen. Hung near the copying machine is a flier for an upcoming conference on "schizoid phenomena." "This may be helpful to some of us . . . " an anonymous staffer wrote in red ink. There's also a cartoon in which a steer, about to be hot-branded, gasps into a pay phone, "Hello? Amnesty International?" And no one knows for sure which staffer composed a detailed but fake memo to Healey a few months ago suggesting that AI sell tickets to executions as a fund-raising tool. "There is a dark side," Healey admits. "It's a defense mechanism."

Whenever possible, Amnesty International arranges tours for its freed prisoners, opportunities for them to both thank and reinspire the people who remembered them when they were behind bars. Taiwanese feminist Lu Hsiu-Lien, adopted as an AI prisoner of conscience by an Albuquerque group and freed last year after serving six years of her 12-year sentence, is traveling the United States now and is expected to stop by the New York office. Yugoslav Momcilo Selic, a samizdat writer jailed for "hostile propaganda," then pardoned and permitted to emigrate after Amnesty International agitation, now practices architecture in Ottawa and will appear at AI's annual meeting in Washington next weekend.

Anatoly Shcharansky, an AI prisoner of conscience for more than eight years, did not stop by the office on his U.S. visit this month. But several staff people went to hear him speak at Yeshiva University. He is one of theirs, they feel. He reminds them of why they do what they do. They quote him, all the time, about how a letter in a jail is like water in a desert.