Universal International Freephone Service is an international service, assigned the country code 800 by the ITU. The intention is that any customer in the world can dial the same number to reach a business subscribing to a number, and at no charge to the calling party. However, only a limited number of countries yet participate. In order to participate, countries must agree on the amount of revenue they will retain (to cover their costs of network transport) while still forwarding sufficient revenue to cover the recipient's costs of subscribing.

UIFS is analogous to intra-national toll free

Toll-free telephone number

A toll-free, Freecall, Freephone, 800, 0800 or 1-800 number is a special telephone number which is free to the calling party, and instead the telephone carrier charges the called party the cost of the call...

numbers such as 800 service in Canada and the United States, and Freephone services in most other countries.