Can someone explain this about sliding window

Question

[josynan9]

I am trying to analyze this with 2 programs .For the first sentence I am using the web program compseq and for the second one Cusp

1. Codons are not read as trinucleotides in a sliding window.
2. Codons are also trinucleotides, but NOT overlapping. These must be read in the correct reading frame.

What are the differences between both ?

[GenoMax]

sliding window can use a step option. When you are reading codons you can use a step of 3 to keep the window in frame once you start with one frame.

Slide the window over by 1 at start to choose next frame.