SDI is one of the leaders in the prepaid calling industry in United States. SDI is continuously helping families and businesses in communicating overseas. SDI is rapidly increasing its wholesale distribution network across the nation. SDI has expanded its products as the industry revolutionizes. SDI's "Black" calling card was launched in March 2010 and continues to be one of the best selling calling cards in the market. Black011 an international pinless top up solution which allows the customer to register up to 10 phone numbers, US cellular top up and RTR has had an overwhelming response in the market. Black Wireless an exclusive prepaid GSM wireless service which offers an affordable unlimited talk, text and data plans that incorporate its direct dial international calling feature at the best available rates. With plans starting at $30.00 with Unlimited Talk, Text, MMS and various Data. All plans have FREE International Calling and Global Text included and a 30 Day Expiration. To complete this value added service, which requires NO inventory and NO investment, SDI implemented International Bill Pay from the Black011 portal. It is also a full functional portal for Black Wireless to activate SIM’s, add airtime plans and port in customers from other services. For more than 18 years we have consistently provided reliable, high-quality products, services and excellent customer service. Become a Distributor or Retailer now.