BT has accepted Oftel's proposals for price controls and will cut customer bills by the rate of inflation.
The changes will benefit four-fifths of the telco's residential customers and are set to come into force next month.
BT said in a statement that the measures will provide an appropriate balance between consumer protection and the flexibility it needs.
The company is one of the first operators to put a cap on the amount of money it takes for calls connected to mobile networks, bringing such charges in line with the price controls.
In September BT is planning to launch a new wholesale line rental product similar to its existing Calls & Access product for service providers, but with enhancements added in the future.
The move will enable other telcos to charge customers for line rental and calls on one bill.
BT added that, once Oftel is satisfied that this new product is starting to have an impact on the retail market, price controls will be looked at again to allow bills to rise at the rate of inflation.
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