MasterCall (formerly known as WDT/Allvoitel) is a popular provider of domestic and international long distance services for landlines and mobile phones. Our products include the choice of local, long distance and wireless services. We provide multilingual customer support seven days a week and 365 days a year. Innovative and state-of-the-art technology is our trademark. As a telecommunications provider, MasteCall is currently a choice of more than 100,000 satisfied customers in the US.