Digital cable technology has allowed cable providers to compress video channels so that they take up less bandwidth and to offer two-way communication capabilities. This has enabled providers to offer more channels, video-on-demand services that don't require a separate telephone line, telephone services, high speed internet services, and interactive television services. Digital cable implements error correction to ensure the integrity of the received signal and uses a secure digital distribution system (i.e. a secure encrypted signal to prevent eavesdropping and theft of service.)