WHILE THEIR SUBURBAN neighbors are warming up the old home-screens for the many-channeled world of cable television, District-dwellers are still light years away from even a test pattern. Cable systems -- and all the eye-popping home delivery services that this revolution in communications promises for subscribers -- are in the works all over the contry, drawing big money and much debate about how franchises should be organized, awarded and used. But the District government has yet to consider how the city might best join this municipal gold rush. It's time to -- and the council is where the moves are due.

It is not, we hasten to note, another old-fashinoned case of D.C. government inertia or red tape. As staff writer Merriall Brown reported in a series of articles on "The Cable Connection," the potentially enormous inpact of cable on the financial, educational and social systems of large cities is uncertain enough to merit caution. Big-city governments have been wise to proceed carefully, since most of their cable franchises will amount to monopolycontracts -- and since they have watched other areas wade into swamps of influence-peddling and politicking over franchise awards.

Not only should any city be careful in its financial arrangements with cable operators; it should also scrutinize the competition for the greatest range of community services -- which could include two-way communications between home viewers and public agencies, schools, cultural institutions or community functions. The huge investments necessary for urban cable systems -- perhaps $60 million to wire the District -- may make local ownership difficult; but maximum participation of local interests -- which in the District means strong minority involvement -- is essential.

Robert L. Johnson, president of District Cablevision, Inc., the first company to announce publicly its plans to seek the D.C. franchise, strongly believes that both the capital and the talent exist in this area to ensure clean, locally controlled and profitable cable operations that will be a strong source of education, entertainment and municipal revenue. But before this can begin to happen, they city government has to develop some expertise in the field.

This is one instance where expert, independent consultants are called for. Costs of such a study could be bourne collectively by, or billed to, all bidders. A council subcommittee headed by Wilhelmina Rolark is already organized to look into the writing of cable ordinances and could give the signal for action right away. Even after legislation is enacted and a bid awarded, it will take at least another three years to wire the city. So it's high time at last to get the city's cable show on the road.