Cable TV customers will soon find a few changes to their channel lineup, and many will need to add equipment to continue watching, according to an announcement from Comcast officials.

Comcast this week will begin sending letters to customers in Corvallis, Albany and Lebanon about plans to begin transmitting channels 32 through 71 digitally, which will require decoder boxes for televisions. Service for people who subscribe to basic cable service, which includes transmission of channels 2 through 31 on analog signals, will remain unchanged.

The company's "expanded basic" customers will see the most difference. On Feb. 11, channels 32 through 71 will change to digital transmission. Customers will need a set-top receiver box in order to watch those channels.

Those subscribers will gain access to music channels, high-definition television and on-demand services when the switch takes place. A number of additional channels will be added. By moving to digital transmission of those channels, the company hopes to free bandwidth for additional services.

Comcast will provide the equipment free of charge to customers, but they must contact the company and request them. Up to one digital converter with access to music and on-demand features and two smaller boxes for television signals only will be provided.

Additional boxes can be rented for $1.99 per month.

Customers who already subscribe to digital cable service will need the smaller converter boxes for televisions that aren't hooked up to the existing set-top box in order to view the digitized channels. Current digital subscribers will also see some new channels.

The change is unrelated to the federally mandated switch in February from over-the-air signals to cable or digital service.