ITC is the local exchange carrier and is not one of the 22 companies that are divested Bell-operating companies. ITCs aren't generally subject to restrictions propsed by the MFJ, but, some of the larger companies are bound by a separate form of consent decrees. From a regulatory point of view Cincinnati Bell and Southern New England Telephone are generally considered ITCs.
Any of over 1,400 local telephone companies that serves a local area not covered by Bell Operating Companies.. Each has a unique sophistication and service offering. The best know are United Telecom, GTE and Rochester Telephone.