Channel used to communicate back to the service provider.
Broadcasting is by definition a one-way one-to-many form of communication.
For interactive services, the return path is used to establish a two-way communication link back to the service provider.
This is also variously referred to as a return channel, reverse channel, or back channel. This channel is often of lower bandwidth or capacity. Typically it is provided using a dial-up modem and attached telephone line, over a cable television system or an attached network.
The availability of a return path enables true interactive services that permit the user to request data and send responses. This may be used, for example to order a service or register a vote.