Old Australian bakelite phone with letters to be used in the prefix of the phone number.
It used to be that Melbourne numbers were in a format similar to WL 2587 - then eventually the letters were dropped and numbers substituted. So then the above number became 85 2587. Later the two digit prefix was divided up into more specific and smaller areas and an extra digit was added - eg 857 2587.
And after that reasonably recently, the dreaded 9 was added - so 9857 2587.