Why do the letters on the telephone start on the "2" and not the "1"?

Why does “ABC” begin on the number two on the phone instead of one?

Why is there no Q on the telephone dial?

The answer to your question appears in the 2nd paragraph.

on an old phone i have here the letters Q & Z are on A
but now they start from 2 and the keys go like this

ABC DEF GHI JKL MNO PQRS TUV WXYZ
2 3 4 5 6 7 8 9