Q. What is inter digit time?
Break time is nominally 61 ms and make time is nominally 39ms. Digits are separated by idle period of 300 ms known as inter digit time. It is vital that switching machine recognize inter digit time so that it can separate pulses from successive digits. Central office switch incorporates a special timeout circuit to make sure that break part of dialing pulse isn't misinterpreted as phone being returned to its on-hook (idle) condition.