Prepaid telephone calls are usually implemented in the company's network using the intelligent network functionality.

For example, when traveling abroad it's usually cheaper to temporarily use a foreign network, for example with a Prepaid telephone calls.

Prepaid telephone calls are a popular way of making telephone calls which allow the caller to control spending without making a commitment with the telephone company.

But much more complex services have since been built on IN, such as Custom Local Area Signaling Services (CLASS) and prepaid telephone calls.