Flat rate tariff models make it possible to have a high volume of phone usage at a very low relative cost. With flat rate tariffs all of the costs relating to the phone line and the calls made are paid at a fixed price, regardless of the amount of actual use. Flat rate tariffs may apply to every kind of telephone call or just for certain connections. Some tariffs include free calls to the fixed-line network, to mobile phones, to certain countries or to participants in a particular network.
Thanks to various different functions, even telephone systems can enable users to make calls at a very low cost. In general, internal calls between those directly connected to the telephone system are free. Modern Internet-based telephone systems make it possible to integrate participants into corporate communications regardless of their location, as well as allowing them to be reached via a uniform corporate telephone number. Depending on the cloud telephone system being used, these participants can also make calls to each other as virtual, internal participants, for free. Even mobile phones can be integrated into these kinds of systems, making the cost of calling them from a landline phone considerably cheaper.
If a telephone system supports Least Cost Routing or if a separate Least Cost Router is installed, this also reduces phone bills. The Least Cost Routing function automatically selects the most favourable telephone provider for a call. In order to do this, it has the call rates for various contractors stored in its system and uses the Call-by-Call method. This means there is no need to compare fee tables manually. If rate tables are regularly updated, the Least Cost Router is still able to find the most favourable supplier even after adjustments to tariffs have been made. A prerequisite for using the Least Cost Router is that the user's own telephone provider allows the Call-by-Call method.