The first rule for Foreign Service wives has always been to keep their mouths shut. Along with wives -- and husbands -- of Army officers, insurance men and politicians, FSO junior and senior spouses soon discover that being outspoken is out.

Especially is this true in regard to Operations Very Important Persons (Ovips) and Congressional Delegations (Codels) -- and even people with introductory letters from the aforesaid, who turn up at the airports expecting to be wined, dined and transported. That's why the old hands were rather surprised when the unwritten law was broken recently by protests from embassy staffers about a Codel visit to London. The anonymous complainers charged that, in the face of budget cuts, diplomatic posts have to neglect serious work to entertain the Codels.

Entertaining Codels or Ovips is nothing new, being an occupational hazard at U.S. posts in the more desirable countries since Benjamin Franklin first represented America in London.

Now the Foreign Service Family Oral History Project (in cooperation with the Association for Diplomatic Studies) has turned up a few stories about Ovips and Codels from the days when government people still could travel by boat. Project interviewers, who have talked to 28 FSO wives and daughters so far, haven't found many such tales because even the families of retired FSOs tend to have lockjaw when it comes to being less than diplomatic. But they have taped many other fascinating memories of Foreign Service families representing the United States in other languages and other cultures; war, rumors of war and lulls between the storms; barbecues and balls; hard and soft currencies; and mansions and hovels -- all the circumstances of true diplomats, who like it where they are and will like it where they're going.

However, perhaps a few of the Codel and Ovip stories they did hear will help the uninitiated understand the London protest.

Apparently Codels are not always properly briefed as to etiquette abroad, especially the necessity for tipping servants, even in private homes. Unfortunately, if they don't tip, their hosts are required to do it out of their own pockets, as Francesca (Mrs. Sheldon) Mills told Oral History project coordinator Jewell Fenzi.

So it was with some relief in the late '50s in Kabul, Afghanistan, that Francesca Mills received the parting remark of her Codel visitor, Sen. Allen Ellender (D-La.).

"I've left a little something for the staff on the top of the bureau," he said. Mills, delighted, went to collect and distribute the largess to her waiting staff, who had worked late into the night to please the senator.

On the bureau was a half-empty pack of prunes the senator had brought along from the Moscow commissary.

Frances (Mrs. Ben) Dixon remembered the time that then vice president Lyndon Johnson arrived on a visit to Thailand. Every effort had been made to position interesting sights along the way from the airport -- elephants pulling logs, etc.

But politician Johnson craved the sight of people with hands to shake. And so when he saw a bus full of voters (if only in Thai elections) stopped along the way, he halted his caravan, mounted the bus and hugged each and every Thai citizen -- to the considerable surprise of the Thais, who don't like to be touched by strangers.

Later, Johnson's staff wrote, asking for reactions to the vice presidential squeeze.

Came the reply from the only Thai willing to speak: "Well, it was rather like hearing an elephant sing."

Penne Laingen, whose husband Bruce was the leader of the heroic Iranian hostages, is one of the project's interviewers. And she has a story of her own from their post in Karachi, Pakistan.

The day was typical. The electricity had been off since dawn, a weekly occurrence. The cook quit. The temperature threatened to surge up and out of the thermometer. The new baby was not happy. And Bruce Laingen called from the embassy with a guess-who's-coming-to-dinner -- Tish Baldrige, then staff director to Jackie Kennedy, then wife of the president.

Penne Laingen, with the aplomb you learn if you stay with your FSO, "borrowed ice from the neighbors, cooked on a kerosene stove and lit the dinner with candlelight."

When Jackie Kennedy later arrived for her Pakistan visit, she brought from Washington as her state gifts photographs of herself and the president, framed in pigskin. The embassy staff, of course, knew what Washington had forgotten -- pigskin is not "clean" to Moslems. So the Laingens had to stay up to remount them in silver frames hastily flown in.

In the next three years, the project, advised by Joan Challinor, hopes to record 400 hours of varied experiences from 1900 to now for the library of the Diplomatic Studies Association. The tapes are being collected along with photographs, diaries, letters and other memorabilia, says Fenzi, a former Foreign Service wife herself.