I know repeaters don't have to have a control operator at the radio in order to transmit given certain conditions are met.
Are there any restrictions to setting up automated stations which transmit upon receiving specific transmissions from their operators or other operators, but do not act as repeaters? I know beacons are a special case in that they transmit on a schedule.
What restrictions apply to unattended, automated stations?
The specific problem I'm trying to solve involves automating a connection between two distant radios. The originating radio needs to make several transmissions in sequence due to a user instructing it to, without giving it specific frequencies, sequences, and data to transmit (ie, the radio decides what to transmit). The receiving radio, however, may not have a control operator nearby. It still has to listen, and if it gets a "call" from the originating radio it needs to respond, even if there's no control operator nearby.
Under what rules would this type of automation be acceptable?