9. MTAS Compatibility Issues

The overwhelming number of long distance calls within the NANP service area are carried by national interexchange carriers (IXC) such as AT&T or MCI. The subscriber's connection to the national IXC is made automatically at the COX by the local carrier using subscriber lists supplied by the national IXCs.

Independent IXCs are now entering the telecommunications market however, permitting subscribers of the national IXCs to occasionally place long distance calls through the independent IXCs when favorable rates dictate. To take advantage such rates however requires the subscriber to include lengthy identifier codes to be included in the address to identify the independent IXC, generally five additional digits. In contrast MTAS implementation will permit interexchange carrier competition on a very simplified basis. MTAS does require however that the access code <n> be restricted to the single value of <1> for subscribers of national IXCs and <0> for independent carriers.

The two digits <yz> following the access code <0> comprise the independent IXC identifier code, to be followed by the area code. The group <0yz> functions as an access code. The identifier codes <yz> can accommodate 100 independent IXCs with identifiers ranging from <00> to <99> and functions solely for accounting purposes.