Listen to this article All telephone users in the 219 and 574 area codes of northern Indiana are encouraged to start using 10-digit dialing instead of seven digit to make local phone calls this month. NITCO customers can start using 10-digit dialing immediately, since all other carriers are now ready to convert to 10 digit dialing. The full transition will be mandatory by Oct. 24 of this year. The Federal Communications Commission is requiring this change to accommodate the implementing of the national â988â National Suicide Prevention Lifeline, which will be fully applied by July 16, 2022. Residential and business customers in the 219 and 574 area codes should be aware of the following: