International Telephone Service 0033 NTT, a leader in international calling International Calls 0033, a high-quality international call service offered by NTT Communications, connects you to more than 230 regions and nations worldwide. NTT Communications, a leader in domestic calls and international calling, gives you high-quality communications to respond to global needs. Ask us how you can reduce your international communications costs. NTT Communications offers discount services in which international calls from cell phones, calls through international ISDN lines, international toll-free services, and calls via Inmarsat are discounted together. We respond to your needs for cost reduction by offering various discount services depending on your uses. Various additional services are available for more convenient use of international call services. A full range of additional services, including international ISDN and international toll-free services, are available to enable you to enjoy more convenient international calling.