If you then wanted to connect to another city, let's say from Calcutta you wanted to call Delhi, you'd have to book something called a trunk call, and then sit by the phone all day, waiting for it to come through.
Si querías conectar con otra ciudad, digamos que querías llamar de Calcuta a Delhi, tenías que reservar una cosa que se llamaba "trunk call" y sentarte delante del teléfono todo el día a esperar que llegara.