I don't know what you mean. The "Not all cellphones" refers to everything in the rest of the sentence so you have :
1) Not all cellphones in the shop are black.
2) Not all the cellphones in the shop might not include TV-out feature.
I'm sure you realise the second is hard to understand. Not all of them exclude the TV-out feature? Not all of them have it? Some of them have it? Do any of them include it?
Student or Learner