Every landline has an option similar to "not in time *69, or redial", etc. Just add a feature to the phone where the subscriber can initiate a prompt for the caller be required to press a specified number in order to proceed with the call. Robo calls will not be able to do this, thus putting a big roadblock in the way of auto dialing. Also, you could program in a feature where the subscribers can pick the number themselves or occasionally change it so everyone in the country is different. This will prevent a work around by telemarketers. You could even take it a step further with a generic prerecorded message saying the person subscribing to this phone has opted not to receive telemarketing calls, take surveys, and receive political calls or solicitations for donations. Press (#) to continue. Anyone proceeding after the message will be in clear violation of the subscriber’s wishes.