The accusatory fingers have been lowered. Claims that the opponent is waffling, rambling or slinging mud have ended.

Replacing the harangue among the five congressional candidates in Northern Virginia is the sound of sweet-voiced teen-age girls and earnest school teachers who have glued telephones to their ears. Except for the hours when professional football games are on television, the callers will be pleading until Tuesday afternoon with "targeted" voters to please go to the polls.

The telephones, according to Delage at and Republican strategists, are the last remaining weapons in two close congressional races that could be decided by who calls whom.

"Either side has enough voters in the 8th and 10th districts to win it if those voters come out," according to Ira M. Lechner, a former state delegate from Arlington and active Democratic organizer.

"These off-year elections are volatile. Whoever has the best vote-pulling organization will win," Lechner said.

"Be enthusiastic, confident and smile," says the sign in front of each of the 10 phone bank callers at 84 District Republican challenger John F. Herrity's campaign headquarters in Springfields.

Smiling through her braces, Herrity's 14-year-old daughter Mary Beth made the pitch last week like this: "Hello, my name is Mary Beth Herrity and I am taking a survey in your neighborhood."

Without stopping or hesitating (as a sign told her told), Mary Beth asked the registered voter on the phone if he was going to vote for Democratic Andrew P. Miller or Republican John W. Warner in the Senate race and for Herrity or Democratic Rep. Herbert E. Harris in the house race.

Those who answered in Herrity is favor will be getting another call on Tuesday. Some voters may get two of more calls just to make sure they vote, according to Herrity's campaign plans.

The race between Herrity and two-term incumbent Harris, which ended with each candidate calling the other a liar, is seen as a toss-up by campaign workers for both sides who have been telephoning registered voters since September.

The final push by Herrity, in addition to the phone operation, included $19,000 in television advertising last week and several mailings, the largest of which was sent to nearly 100,000 voters.

One of Herrity's six mailings, which went last week to a selected group of 3,000 voters, prompted one of Northern Virginia's most vicious rounds of campaign phetovic in recent elections.

Harris called the letter, which accused him of voting against stiff penalties for child pornographers, a lie and a "last-minute smear." Herrity called Harris' attempt to explain his vote "a lie."

In the 10th District, where Republican challenger Frank Wolf has run a strong campaign against incumbent Democrat Rep. Joseph L. Fisher, massive phone and mailing efforts have also dovetailed in the last week of the campaign with personal attacks between the candidates.

Wolf, who spent $25,000 for television commercials last week, accused Fisher of misrepresenting his opposition to Interstate Rte. 66 to voters in parts of the district that support completion of the highway from the Capital Beltway to the Potomac River.

Fisher, who has bought no television time in the campaign but who mailed 140,000 letters last week, reluctantly shed his professional reserve in the last week of the campaign and called some of Wolf's "non-issues" as "stupid."

Campaign managers for the four major congressional candidates agree that while television advertising and mass mailings are important, the best way to win a seat in Congress from Northern Virginia is to use the telephone effectively.

Part of being effective with the phone, the campaign managers say, is knowing when not to use it. "The first thing you do is you get a Redskin schedule and you work around it." said Adele Schaefer, phone bank coordinator for the Fairfax County Democratic Committee.

"If you know anything about politics in this area you know that it would be foolish to make calls after 9 p.m. this Monday night (when the Redskins play the Baltimore Colts on national television)." Schaefer said.

Schaefer said she has alerted her callers to be sensitive to the callees earlier on Monday evening in case they may be watching a televised pre-game show. "We'll stop, if we get bad vibes," she said.

The campaign ended their door-to-door convassing of voters earlier last week and spent the last days before the weekend "merging and purging" computer printouts with lists of favorable voters obtained by phone and door-to-door canvassing.

"We've got to be careful when we put those lists together that we don't get any overlap," said Don Allen, Herrity's campaign manager. "If we call the same people twice by mistake, they might get mad and not vote at all."

A major worry among the campaign workers is voter turnout, with nearly everyone agreeing that an unusually low turnout will be bad for their candidate.

Mel Rappleyea, secretary of the Fairfax County electoral board, said that he expects a higher-than-normal turnout for a nonpresidential election. In 1974, the turnout was 56 percent in the 8th District. This year, Rappleyea said that based on last-minute registration and a high number of absentee ballots already turned in turnout should be more than 60 percent. Turnout in the 10th District, he said, will be almost as high.

If voter turnout does go that high, prognosticators for both parties say the results will be anyone's guess.

Joseph Wisniewski, vice chairman of the Fairfax Democratic Committee, said the high turnover of voters in Northern Virginia (figured to be as high as 32 percent) makes any prediction based on normal voter turnout somewhat suspect.

"But if the turnout goes above 56 percent, we don't know what the hell the voters are going to do," Wisniewski said.

There is one candidate in Northern Virginia - independent Charles E. Coe, running in the 8th District - who maintains that what voters do on Tuesday is their own business.

Coe's last-minute campaign activities consist only of riding around shopping centers and parking lots - where he says, "the action is" - in a station wagon, which is equipped with a public address system, and repeating: "A vote for Coe is a vote for you."