I always enjoy reading about this kind of stuff even though a lot of is only applicable in the US. On UK landlines you can dial 17070 to access BT line test fu

I always enjoy reading about this kind of stuff even though a lot of is only applicable in the US. On UK landlines you can dial 17070 to access BT line test functions. When you dial a very well spoken voice reads your phone number back to you. It's rarely been useful to me but I did once astonish someone by using it, they were convinced it was meant to be a secret number and that I was probably breaking the law!