The eight competing cable firms that have submitted proposals to Prince George's County range in size from Metrovision of Prince George's County, a subsidiary of the $1.2 billion Newhouse Publishing empire, to Prince George's Community Cablevision, two-thirds owned by county residents. All the companies offer similar basic services.

Basic service begins with 17 to 20 channels that carry all the metropolitan Washington and Baltimore broadcast stations, with reception that is free of interference associated with conventional over-the-air transmission. In addition, there are 8 to 27 community-access and local service channels offering air time to county and local governments, educational and religious institutions, and consumer or informational services. Most firms offer these packages of services at $4 and 6 per month to the subscriber. Some companies, however, offer one or both of the services free after installation charges ranging from $15 to $30. Many companies will waive installation charges when service first becomes available, during periodic promotions or as a bonus to subscribers who purchase additional services.

For additional monthly charges of $2 to $8, subscribers can receive nationally distributed sports, news and entertainment channels such as the Entertainment and Sports Network, Atlanta entrepreneur Ted Turner's Cable News Network, New York's WOR-TV and dozens of other channels geared to specific interests.

Finally, there are premium offerings for an additional $5 to $7 per month. These include movies on the popular Home Box Office and other channels showing current films.

The county system also will have at least two and as many as eight two-way channels that allow subscribers to respond to polls and to shop and bank at home. Other two-way services now under development are expected to be offered in the future.

More channels will be available for clear FM radio reception, newspaper and other text material, home security and other services, brining the system's potential to 100 to 118 channels of programming.

Using the northern area franchise as an example, the proposed cable system envisioned by the companies will cost $26 million to $41 million to build. Major competitors Storer and Cross Country Cable project revenues of $7 to $10 million annually just two years after the franchise is awarded. The county will receive 5 percent of the gross -- $350,000 to $500,000, using the above fifth-year estimates. The two companies project profits before depreciation in the fifth year at $4 million to $5 million.