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

Factual Questions
1

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

2

Why is there no Q on the telephone dial?

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

3

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