Abstract: A method and apparatus for calculating charges for telephone calls in real time. The operator assistance switch connected to an originating telephone customer recognizes that a call is one which requires an immediate calculation of charges. Such calls include coin calls, calls from certain types of hotel/motel private branch exchanges, calls from customers who wish to be notified as to the amount of the charge for the call they are about to place, and calls from customers requesting a rate for a call to a particular destination. The operator assistance switch generates a message including the originating and terminating directory numbers and the type of the call. The message is sent to a shared rating system which uses the parameters sent in the message to calculate charges. The shared rating system then sends a message, including the calculated charges, back to the operator assistance switch. The customer, or the hotel/motel private branch exchange, is then notified of the amount of the charges.