Calabra, S.A., a Peruvian corporation, manufactures inventory in Peru. The inventory is sold to independent distributors in the United States, with title passing to the purchaser in the United States. Calabra has no employees or operations within the United States. All sales activities are conducted via telephone and internet communication between Calabra's home office and its U.S. customers. Explain whether Calabra incurs any income effectively connected with a U.S. trade or business.