Under what condition would a customer on the basic service tier of digital cable need a digital terminal adapter (DTA) installed?

A digital terminal adapter (DTA) is required when the cable operator encrypts the service tier to ensure that only authorized subscribers can access the content. When the basic service tier is encrypted, customers must have a DTA to decrypt the signal and gain access to the channels included in that tier. Without the adapter, the customer would be unable to view the channels they are paying for since the encrypted signal cannot be processed by standard equipment.

The scenario in which the cable operator chooses to apply encryption specifically impacts those customers who are on the basic tier, as they would otherwise receive unencrypted signals. If encryption is applied to a service tier that a customer is subscribed to, the DTA becomes necessary for access to the content, ensuring that the customer can utilize the channels provided under their tier subscription.