I call a "channel" the frequency of a station; "program number" is what the TV gives me on the remote control to go to a station - the number on the screen. In

I call a "channel" the frequency of a station; "program number" is what the TV gives me on the remote control to go to a station - the number on the screen. In that framework, the TV has two frequencies (or channels) associated to the same "program number". I can switch between the two by entering from the remote the same "program number" twice or more times...