Mayor Marion Barry sent the City Council emergency legislation yesterday that would grant most of the financial concessions sought by the firm hired to build the city's cable television system, but not a controversial provision that could relieve it of having to wire every home if that becomes too costly.

In seeking council action today to try to salvage the financially troubled cable franchise, Barry said he has "serious reservations" about District Cablevision Inc.'s request for an escape clause if the cost of wiring every home exceeds an average of $500 per unit. At the same time, the mayor left open the door for consideration of imposing a ceiling on the firm's construction costs after the emergency legislation expires in 90 days.

"Ninety days from now we will have a detailed construction schedule which will give us a better sense of the net effect of the $500 cap," Barry said in a letter to City Council Chairman David Clarke accompanying the legislation.

District Cablevision President Robert L. Johnson said yesterday that immediately after the council adopts emergency legislation, his firm will begin preparing construction schedule and working out a financial agreement with Tele-Communications Inc., the Denver-based cable television company that has offered to invest $30 million in the District project if the council approved the concessions.

Johnson said that District Cablevision also would renegotiate its contract with the Chesapeake & Potomac Telephone Co., which has agreed to construct, maintain and own the cable transport lines.

Barry has urged the council to vote today, before it recesses for the summer, but council member Betty Ann Kane (D-At Large), chairman of the council's cable committee plans to recommend that the council delay action and demand more information from the city's cable firm.

District Cablevision Inc., which signed a 15-year cable franchise agreement with the city in February, told the council last week it needed $32 million worth of concessions, as well as the escape clause, before it could obtain the necessary backing from TCI, the nation's largest cable operator.

But Clarke said Johnson told him yesterday that he was willing to drop his demand for the $500 per unit average construction limit.

Johnson, contacted later, insisted he had merely told Clarke that he had agreed with the mayor not to make the limit a part of the proposed emergency legislation. Johnson said he "supports the mayor's request for emergency legislation" but refused to comment on whether his company would continue to insist that the $500 limit is necessary to secure financing from TCI.

John Sie, a TCI vice president, said yesterday that his company needs "some sort of economic viability measure" but not necessarily in the form of a $500 per unit average construction limit. Sie said that his company is also committed to wiring the entire city, but has had trouble convincing city officials of this.

"The way it is being portrayed is that we don't want to build the [system] downtown and that's not true," Sie said. "We are wedded to universal construction. Because there is some confusion on that, we have to have a better dialogue with the city on that."

Clarke said TCI may not get all that it wants from the council.

"TCI will get what it gets," Clarke said. "It has been put to us, 'Take it or leave it,' and what we have had is a hardnose public negotiation game."

Kane said she plans to recommend that the council adopt a resolution, rather than binding legislation, that would serve as the council's "letter of intent" on District Cablevision's proposed modifications.

Kane's resolution would require District Cablevision to supply the council with a construction schedule and map detailing plans for each neighborhood and a legally binding "memorandum of understanding" with C&P and TCI. Kane said she also wants to know the extent of TCI's ownership interest once it provides financing for the system and "the controls TCI shall assert" regarding management of the system.

"The council members are looking for something to express where we are but not lock ourselves in if this doesn't work out," said Kane. "I'm assuming that [District Cablevision] would be better off with a resolution that is not binding rather than emergency legislation that flatly turns them down on some provisions."

But Johnson said a council resolution would be "absolutely" unacceptable because it would not give his company the type of "firm statement" needed from the city.

The concessions proposed by Barry would allow District Cablevision to reduce the number of residential cable channels from 78 to 60, delay activation of a separate institutional cable network, delay payments to the city and substantially reduce the firm's financial commitments to the development of community and municipal programs.