Hi Sunshar,
I believe I can explain what is happening. Part of the issue is the type of technology Cox it utilizing to transmit video services, and part of the issue is a default function of the cable receiver.
Cox, along with almost all other cable TV providers, utilizes Switched Digital Video (SDV) technology to broadcast to a customer only the cable TV channels that a customer is actively viewing or recording.
With traditional broadcasting, all TV signals are broadcast constantly to the customer’s digital set top receiver, whether the customer watches them or not. This requires large amounts of dedicated bandwidth. By sending signals only for programs the customer is watching or recording, switched digital video significantly improves bandwidth efficiency and allows Cox to continue meeting customer demands for more video services, such as more HD programming, more digital cable channels, and other new digital video services.
When your cable box turns itself to channel 7, it means that the TV has been on a SDV channel for an extended period of time without anyone touching the remote (usually 2-4 hours.) It was originally designed by cable box manufacturers as an auto power-down feature to conserve power.
I know it's annoying, and I totally apologize. We are working on a fix with the set top box manufacturer; we just don't know how long it will be before a fix is available. For the time being, try to think about pushing a button (personally, I'm fond of MUTE during commercials) at least once during a show or a movie, and the channel shouldn't change on its own anymore.
