The Fairfax City Council has taken its first major step in bringing cable television to the community's 20,500 residents.

In a unanimous vote last Tuesday, the council approved a 35-page regulatory ordinance that guarantees local public broadcasting on the cable system, protects the city from possible default by a cable company and requires the cable operator to pay the city a maximum $50,000 franchise fee and a percentage of its gross receipts.

"The city won't get rich off that, but it will be additional money coming into our coffers," one official said last week.

The ordinance, which will be followed Oct. 12 by a council vote on more detailed bid specifications, also requires the cable franchise to transmit at least 35 different channels, transmit in color and keep abreast of changes in cable TV technology.

Some city officials said last week they expect Media General, which recently was awarded the lucrative Fairfax County franchise, and the Reston-based Warner Cable to vie for the Fairfax City franchise. Media General may have a leg up on its competitor since it plans to wire several Fairfax County buildings in the city for cable.

City officials hope to have bids for the franchise by Jan. 1 and to award the franchise next spring. It could take 18 months to two years before cable is available to all of the community's 7,200 houses, apartments and condominiums.

In portions of the city with buried phone and electrical cables, the TV cable also will have to be buried, officials said.