Downstream (TV) - The route the signal or data takes from its origin (such as satellite, cable, telco or household antenna) to its final destination, your TV.  "Upstream" is the opposite. Literally the downstream comes to you. "Upstream" is what goes from your TV system back to the network operator. Downstream might mean the digital transmission path from a central site or Internet Service Provider (ISP), to the user (customer). In cable TV, it's typically from the headend to the enduser (subscriber.)

See the Interactive Television Institute.