I don’t know exactly - by the time I was a kid, pay phones were push-button (although still pulse rather than tone, right through until mobile phones took over) and microprocessor-managed, so the system could recognise when calls were to freephone numbers, standard rate, or premium rate lines.
I would have thought that would be a task for the telephone exchange?
It’s the tying it in to payment that was managed by the phone. These later models would not connect to a chargeable number unless coins had already been inserted, but still had to be able to handle freephone calls, dialling the operator, etc.
This topic was automatically closed after 5 days. New replies are no longer allowed.
