Reference Data Rate Center Directory SINAI, SD Rate Center SINAI — SD Data last updated: March 10, 2026 LATA 640 State SD Area Codes 1 Exchanges (NXX) 1 Carriers 1 Coordinates 44.24430613164504, -97.04030939004508 Area Codes 605 Top Carriers Carrier OCN NXX Count INTERSTATE TELECOM COOP, INC. - SD 1651 1
